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<!-- Copyright (c) 2003 Teknowledge Corporation. 


This dictionary database was created by Jay F. Kominek
<jkominek@miranda.org> (Feel free to send any comments, additions,
corrections, money to that address) It was compiled from a variety of
sources, and is in my opinion, a work of my own. (The only stuff that
was really copied verbatim was the atomic numbers and weights, please,
I'd like to see someone try and exert a copyright on the values of
atoms.)  So, I place this in the public domain, if it somehow breaks,
you get to keep both pieces. It'd be nice if you kept the fact that I
compiled the information in here, but is not needed.
Up to date copies can probably be found on the web at:
http://www.miranda.org/~jkominek/elements/

This information has been converted to KIF by Adam Pease at Teknowledge.
This file (unlike many of our other ontology files, which are released
under GNU license) is being released in the public domain, in keeping
with the view of the original compiler of the material.

-->

<rdfs:Class rdf:ID= "Actinium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Actinium</rdfs:label>

<atomicNumber>89</atomicNumber>

<rdfs:comment>Silvery radioactive metallic element, belongs to 

group 3 of the periodic table.  The most stable isotope, Ac-227, has a 

half-life of 217 years.  Ac-228 (half-life of 6.13 hours) also occurs in 

nature.  There are 22 other artificial isotopes, all radioactive and 

having very short half-lives.  Chemistry similar to lanthanum.  Used as a 

source of alpha particles.  Discovered by A.  Debierne in 1899.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Aluminum">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Aluminum</rdfs:label>

<atomicNumber>13</atomicNumber>

<rdfs:comment>Silvery-white lustrous metallic element of group 

3 of the periodic table.  Highly reactive but protected by a thin 

transparent layer of the oxide which quickly forms in air.  There are many 

alloys of aluminum, as well as a good number of industrial uses.  Makes up 

8.1 percent of the Earth's crust, by weight.  Isolated in 1825 by H.C.  

Oersted.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Americium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Americium</rdfs:label>

<atomicNumber>95</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element, 

belongs to the actinoids.  Ten known isotopes.  Am-243 is the most stable 

isotope, with a half-life of 7.95*10^3 years.  Discovered by Glenn T.  

Seaborg and associates in 1945, it was obtained by bombarding 

{uranium}-238 with alpha particles.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Antimony">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Antimony</rdfs:label>

<atomicNumber>51</atomicNumber>

<rdfs:comment>Element of group 15.  Multiple allotropic forms.  

The stable form of antimony is a blue-white metal.  Yellow and black 

antimony are unstable non-metals.  Used in flame-proofing, paints, 

ceramics, enamels, and rubber.  Attacked by oxidizing acids and halogens.  

First reported by Tholden in 1450.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Argon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Argon</rdfs:label>

<atomicNumber>18</atomicNumber>

<rdfs:comment>Monatomic noble gas.  Makes up 0.93 percent of the 

air.  Colourless, odorless.  Is inert and has no true compounds.  Lord 

Rayleigh and Sir william Ramsey identified argon in 1894.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Arsenic">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Arsenic</rdfs:label>

<atomicNumber>33</atomicNumber>

<rdfs:comment>Metalloid element of group 15.  There are three 

allotropes, yellow, black, and grey.  Reacts with halogens, concentrated 

oxidizing acids and hot alkalis.  Albertus Magnus is believed to have been 

the first to isolate the element in 1250.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Astatine">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Astatine</rdfs:label>

<atomicNumber>85</atomicNumber>

<rdfs:comment>Radioactive halogen element.  Occurs naturally 

from uranium and thorium decay.  At least 20 known isotopes.  At-210, the 

most stable, has a half-life of 8.3 hours.  Synthesized by nuclear 

bombardment in 1940 by D.R.  Corson, K.R.  MacKenzie and E.  Segre at the 

University of California.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Barium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Barium</rdfs:label>

<atomicNumber>56</atomicNumber>

<rdfs:comment>Silvery-white reactive element, belonging to group 

2 of the periodic table.  Soluble barium compounds are extremely 

poisonous.  Identified in 1774 by Karl Scheele and extracted in 1808 by 

Humphry Davy.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Berkelium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Berkelium</rdfs:label>

<atomicNumber>97</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element.  

Belongs to actinoid series.  Eight known isotopes, the most common Bk-247, 

has a half-life of 1.4*10^3 years.  First produced by Glenn T.  Seaborg 

and associates in 1949 by bombarding americium-241 with alpha 

particles.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Beryllium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Beryllium</rdfs:label>

<atomicNumber>4</atomicNumber>

<rdfs:comment>Grey metallic element of group 2 of the periodic 

table.  Is toxic and can cause severe lung diseases and dermatitis.  Shows 

high covalent character.  It was isolated independently by F.  Wohler and 

A.A.  Bussy in 1828.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Bismuth">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Bismuth</rdfs:label>

<atomicNumber>83</atomicNumber>

<rdfs:comment>White crystalline metal with a pink tinge, belongs 

to group 15.  Most diamagnetic of all metals and has the lowest thermal 

conductivity of all the elements except mercury.  Lead-free bismuth 

compounds are used in cosmetics and medical procedures.  Burns in the air 

and produces a blue flame.  In 1753, C.G. Junine first demonstrated that 

it was different from lead.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Boron">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Boron</rdfs:label>

<atomicNumber>5</atomicNumber>

<rdfs:comment>An element of group 13 of the periodic table.  There 

are two allotropes, amorphous boron is a brown power, but metallic boron 

is black.  The metallic form is hard (9.3 on Mohs' scale) and a bad 

conductor in room temperatures.  It is never found free in nature.  

Boron-10 is used in nuclear reactor control rods and shields.  It was 

discovered in 1808 by Sir Humphry Davy and by J.L.  Gay-Lussac and L.J.  

Thenard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Bromine">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Bromine</rdfs:label>

<atomicNumber>35</atomicNumber>

<rdfs:comment>Halogen element.  Red volatile liquid at room 

temperature.  Its reactivity is somewhere between chlorine and iodine.  

Harmful to human tissue in a liquid state, the vapour irritates eyes and 

throat.  Discovered in 1826 by Antoine Balard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Cadmium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Cadmium</rdfs:label>

<atomicNumber>48</atomicNumber>

<rdfs:comment>Soft bluish metal belonging to group 12 of the 

periodic table.  Extremely toxic even in low concentrations.  Chemically 

similar to zinc, but lends itself to more complex compounds.  Discovered 

in 1817 by F.  Stromeyer.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Caesium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Caesium</rdfs:label>

<atomicNumber>55</atomicNumber>

<rdfs:comment>Soft silvery-white metallic element belonging to 

group 1 of the periodic table.  One of the three metals which are liquid 

at room temperature.  Cs-133 is the natural, and only stable, isotope.  

Fifteen other radioisotopes exist.  Caesium reacts explosively with cold 

water, and ice at temperatures above 157K.  Caesium hydroxide is the 

strongest base known.  Caesium is the most electropositive, most alkaline 

and has the least ionization potential of all the elements.  Known uses 

include the basis of atomic clocks, catalyst for the hydrogenation of some 

organic compounds, and in photoelectric cells.  Caesium was discovered by 

Gustav Kirchoff and Robert Bunsen in Germany in 1860 spectroscopically.  

Its identification was based upon the bright blue lines in its spectrum.  

The name comes from the latin word caesius, which means sky blue.  Caesium 

should be considered highly toxic.  Some of the radioisotopes are even 

more toxic.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Calcium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Calcium</rdfs:label>

<atomicNumber>20</atomicNumber>

<rdfs:comment>Soft grey metallic element belonging to group 2 of 

the periodic table.  Used a reducing agent in the extraction of thorium, 

zirconium and uranium.  Essential element for living organisms.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Californium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Californium</rdfs:label>

<atomicNumber>98</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element.  

Belongs to actinoid series.  Cf-251 has a half life of about 700 years.  

Nine isotopes are known.  Cf-252 is an intense {neutron} source, which 

makes it an intense {neutron} source and gives it a use in {neutron} 

activation analysis and a possible use as a radiation source in medicine.  

First produced by Glenn T.  Seaborg and associates in 1950.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Carbon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Carbon</rdfs:label>

<atomicNumber>6</atomicNumber>

<rdfs:comment>Carbon is a member of group 14 of the periodic 

table.  It has three allotropic forms of it, diamonds, graphite and 

fullerite.  Carbon-14 is commonly used in radioactive dating.  Carbon 

occurs in all organic life and is the basis of organic chemistry.  Carbon 

has the interesting chemical property of being able to bond with itself, 

and a wide variety of other elements.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Cerium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Cerium</rdfs:label>

<atomicNumber>58</atomicNumber>

<rdfs:comment>Silvery metallic element, belongs to the 

lanthanoids.  Four natural isotopes exist, and fifteen radioactive 

isotopes have been identified.  Used in some rare-earth alloys.  The 

oxidized form is used in the glass industry.  Discovered by Martin .H.  

Klaproth in 1803.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Chlorine">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Chlorine</rdfs:label>

<atomicNumber>17</atomicNumber>

<rdfs:comment>Halogen element.  Poisonous greenish-yellow gas.  

Occurs widely in nature as sodium chloride in seawater.  Reacts directly 

with many elements and compounds, strong oxidizing agent.  Discovered by 

Karl Scheele in 1774.  Humphrey David confirmed it as an element in 

1810.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Chromium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Chromium</rdfs:label>

<atomicNumber>24</atomicNumber>

<rdfs:comment>Hard silvery transition element.  Used in 

decorative electroplating.  Discovered in 1797 by Vauquelin.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Cobalt">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Cobalt</rdfs:label>

<atomicNumber>27</atomicNumber>

<rdfs:comment>Light grey transition element.  Some meteorites 

contain small amounts of metallic cobalt.  Generally alloyed for use.  

Mammals require small amounts of cobalt salts.  Cobalt-60, an artificially 

produced radioactive isotope of Cobalt is an important radioactive tracer 

and cancer-treatment agent.  Discovered by G.  Brandt in 1737.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Copper">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Copper</rdfs:label>

<atomicNumber>29</atomicNumber>

<rdfs:comment>Red-brown transition element.  Known by the Romans 

as 'cuprum.' Extracted and used for thousands of years.  Malleable, 

ductile and an excellent conductor of heat and electricity.  When in moist 

conditions, a greenish layer forms on the outside.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Curium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Curium</rdfs:label>

<atomicNumber>96</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element.  Belongs 

to actinoid series.  Nine known isotopes, Cm-247 has a half-life of 

1.64*10^7 years.  First identified by Glenn T.  Seaborg and associates in 

1944, first produced by L.B.  Werner and I.  Perlman in 1947 by bombarding 

americium-241 with {neutron}s.  Named for Marie Curie.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Dysprosium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Dysprosium</rdfs:label>

<atomicNumber>66</atomicNumber>

<rdfs:comment>Metallic with a bright silvery-white lustre.  

Dysprosium belongs to the lanthanoids.  It is relatively stable in air at 

room temperatures, it will however dissolve in mineral acids, evolving 

hydrogen.  It is found in from rare-earth minerals.  There are seven 

natural isotopes of dysprosium, and eight radioisotopes, Dy-154 being the 

most stable with a half-life of 3*10^6 years.  Dysprosium is used as a 

neutron absorber in nuclear fission reactions, and in compact disks.  It 

was discovered by Paul Emile Lecoq de Boisbaudran in 1886 in France.  Its 

name comes from the Greek word dysprositos, which means hard to obtain.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Einsteinium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Einsteinium</rdfs:label>

<atomicNumber>99</atomicNumber>

<rdfs:comment>Appearance is unknown, however it is most 

probably metallic and silver or gray in color.  Radioactive metallic 

transuranic element belonging to the actinoids.  Es-254 has the longest 

half-life of the eleven known isotopes at 270 days.  First identified by 

Albert Ghiorso and associates in the debris of the 1952 hydrogen bomb 

explosion.  In 1961 the first microgram quantities of Es-232 were 

separated.  While einsteinium never exists naturally, if a sufficient 

amount was assembled, it would pose a radiation hazard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Erbium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Erbium</rdfs:label>

<atomicNumber>68</atomicNumber>

<rdfs:comment>Soft silvery metallic element which belongs to the 

lanthanoids.  Six natural isotopes that are stable.  Twelve artificial 

isotopes are known.  Used in nuclear technology as a neutron absorber.  It 

is being investigated for other possible uses.  Discovered by Carl G.  

Mosander in 1843.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Europium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Europium</rdfs:label>

<atomicNumber>63</atomicNumber>

<rdfs:comment>Soft silvery metallic element belonging to the 

lanthanoids.  Eu-151 and Eu-153 are the only two stable isotopes, both of 

which are {neutron} absorbers.  Discovered in 1889 by Sir William 

Crookes.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Fermium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Fermium</rdfs:label>

<atomicNumber>100</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element, belongs 

to the actinoids.  Ten known isotopes, most stable is Fm-257 with a 

half-life of 10 days.  First identified by Albert Ghiorso and associates 

in the debris of the first hydrogen-bomb explosion in 1952.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Fluorine">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Fluorine</rdfs:label>

<atomicNumber>9</atomicNumber>

<rdfs:comment>A poisonous pale yellow gaseous element belonging 

to group 17 of the periodic table (The halogens).  It is the most 

chemically reactive and electronegative element.  It is highly dangerous, 

causing severe chemical burns on contact with flesh.  Fluorine was 

identified by Scheele in 1771 and first isolated by Moissan in 1886.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Francium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Francium</rdfs:label>

<atomicNumber>87</atomicNumber>

<rdfs:comment>Radioactive element, belongs to group 1 of the 

periodic table.  Found in uranium and thorium ores.  The 22 known isotopes 

are all radioactive, with the most stable being Fr-223.  Its existence was 

confirmed in 1939 by Marguerite Perey.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Gadolinium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Gadolinium</rdfs:label>

<atomicNumber>64</atomicNumber>

<rdfs:comment>Soft silvery metallic element belonging to the 

lanthanoids.  Seven natural, stable isotopes are known in addition to 

eleven artificial isotopes.  Gd-155 and Gd-157 and the best neutron 

absorbers of all elements.  Gadolinium compounds are used in electronics.  

Discovered by J.C.G Marignac in 1880.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Gallium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Gallium</rdfs:label>

<atomicNumber>31</atomicNumber>

<rdfs:comment>Soft silvery metallic element, belongs to group 13 

of the periodic table.  The two stable isotopes are Ga-69 and Ga-71.  

Eight radioactive isotopes are known, all having short half-lives.  

Gallium Arsenide is used as a semiconductor.  Corrodes most other metals 

by diffusing into their lattice.  First identified by Francois Lecoq de 

Boisbaudran in 1875.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Germanium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Germanium</rdfs:label>

<atomicNumber>32</atomicNumber>

<rdfs:comment>Lustrous hard metalloid element, belongs to 

group 14 of the periodic table.  Forms a large number of organometallic 

compounds.  Predicted by Mendeleev in 1871, it was actually found in 1886 

by Winkler.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Gold">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Gold</rdfs:label>

<atomicNumber>79</atomicNumber>

<rdfs:comment>Gold is gold colored.  It is the most malleable and 

ductile metal known.  There is only one stable isotope of gold, and five 

radioisotopes of gold, Au-195 being the most stable with a half-life of 

186 days.  Gold is used as a monetary standard, in jewelry, dentistry, 

electronics.  Au-198 is used in treating cancer and some other medical 

conditions.  Gold has been known to exist as far back as 2600 BC.  Gold 

comes from the Anglo-Saxon word gold.  Its symbol, Au, comes from the 

Latin word aurum, which means gold.  Gold is not particularly toxic, 

however it is known to cause damage to the liver and kidneys in some.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Hafnium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Hafnium</rdfs:label>

<atomicNumber>72</atomicNumber>

<rdfs:comment>Silvery lustrous metallic transition element.  

Used in tungsten alloys in filaments and electrodes, also acts as a 

neutron absorber.  First reported by Urbain in 1911, existence was finally 

established in 1923 by D.  Coster, G.C.  de Hevesy in 1923.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Helium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Helium</rdfs:label>

<atomicNumber>2</atomicNumber>

<rdfs:comment>Colourless, odourless gaseous nonmetallic element.  

Belongs to group 18 of the periodic table.  Lowest boiling point of all 

elements and can only be solidified under pressure.  Chemically inert, no 

known compounds.  Discovered in the solar spectrum in 1868 by Lockyer.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Holmium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Holmium</rdfs:label>

<atomicNumber>67</atomicNumber>

<rdfs:comment>Relatively soft and malleable silvery-white 

metallic element, which is stable in dry air at room temperature.  It 

oxidizes in moist air and at high temperatures.  It belongs to the 

lanthanoids.  A rare-earth metal, it is found in the minerals monazite and 

gadolinite.  It possesses unusual magnetic properties.  One natural 

isotope, Ho-165 exists, six radioisotopes exist, the most stable being 

Ho-163 with a half-life of 4570 years.  Holmium is used in some metal 

alloys, it is also said to stimulate the metabolism.  Discovered by Per 

Theodor Cleve and J.L.  Soret in Switzerland in 1879.  The name homium 

comes from the Greek word Holmia which means Sweden.  While all holmium 

compounds should be considered highly toxic, initial evidence seems to 

indicate that they do not pose much danger.  The metal's dust however, is 

a fire hazard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Hydrogen">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Hydrogen</rdfs:label>

<atomicNumber>1</atomicNumber>

<rdfs:comment>Colourless, odourless gaseous chemical element.  

Lightest and most abundant element in the universe.  Present in water and 

in all organic compounds.  Chemically reacts with most elements.  

Discovered by Henry Cavendish in 1776.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Indium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Indium</rdfs:label>

<atomicNumber>49</atomicNumber>

<rdfs:comment>Soft silvery element belonging to group 13 of the 

periodic table.  The most common natural isotope is In-115, which has a 

half-life of 6*10^4 years.  Five other radioisotopes exist.  Discovered in 

1863 by Reich and Richter.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Iodine">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Iodine</rdfs:label>

<atomicNumber>53</atomicNumber>

<rdfs:comment>Dark violet nonmetallic element, belongs to group 

17 of the periodic table.  Insoluble in water.  Required as a trace 

element for living organisms.  One stable isotope, I-127 exists, in 

addition to fourteen radioactive isotopes.  Chemically the least reactive 

of the halogens, and the most electropositive metallic halogen.  

Discovered in 1812 by Courtois.  </rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Iridium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Iridium</rdfs:label>

<atomicNumber>77</atomicNumber>

<rdfs:comment>Very hard and brittle, silvery metallic transition 

element.  It has a yellowish cast to it.  Salts of iridium are highly 

colored.  It is the most corrosion resistant metal known, not attacked by 

any acid, but is attacked by molten salts.  There are two natural isotopes 

of iridium, and 4 radioisotopes, the most stable being Ir-192 with a 

half-life of 73.83 days.  Ir-192 decays into {platinum}, while the other 

radioisotopes decay into {osmium}.  Iridium is used in high temperature 

apparatus, electrical contacts, and as a hardening agent for platinum.  

Discovered in 1803 by Smithson Tennant in England.  The name comes from 

the Greek word iris, which means rainbow.  Iridium metal is generally 

non-toxic due to its relative unreactivity, but iridium compounds should 

be considered highly toxic.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Iron">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Iron</rdfs:label>

<atomicNumber>26</atomicNumber>

<rdfs:comment>Silvery malleable and ductile metallic transition 

element.  Has nine isotopes and is the fourth most abundant element in the 

earth's crust.  Required by living organisms as a trace element (used in 

hemoglobin in humans.) Quite reactive, oxidizes in moist air, displaces 

hydrogen from dilute acids and combines with nonmetallic elements.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Krypton">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Krypton</rdfs:label>

<atomicNumber>36</atomicNumber>

<rdfs:comment>Colorless gaseous element, belongs to the noble 

gases.  Occurs in the air, 0.0001 percent by volume.  It can be extracted 

from liquid air by fractional distillation.  Generally not isolated, but 

used with other inert gases in fluorescent lamps.  Five natural isotopes, 

and five radioactive isotopes.  Kr-85, the most stable radioactive 

isotope, has a half-life of 10.76 years and is produced in fission 

reactors.  Practically inert, though known to form compounds with 

{fluorine}.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Lanthanum">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Lanthanum</rdfs:label>

<atomicNumber>57</atomicNumber>

<rdfs:comment>(From the Greek word lanthanein, to line hidden) 

Silvery metallic element belonging to group 3 of the periodic table and 

oft considered to be one of the lanthanoids.  Found in some rare-earth 

minerals.  Twenty-five natural isotopes exist.  La-139 which is stable, 

and La-138 which has a half-life of 10^10 to 10^15 years.  The other 

twenty-three isotopes are radioactive.  It resembles the lanthanoids 

chemically.  Lanthanum has a low to moderate level of toxicity, and should 

be handled with care.  Discovered in 1839 by C.G.  Mosander.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Lawrencium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Lawrencium</rdfs:label>

<atomicNumber>103</atomicNumber>

<rdfs:comment>Appearance unknown, however it is most likely 

silvery-white or grey and metallic.  Lawrencium is a synthetic rare-earth 

metal.  There are eight known radioisotopes, the most stable being Lr-262 

with a half-life of 3.6 hours.  Due to the short half-life of lawrencium, 

and its radioactivity, there are no known uses for it.  Identified by 

Albert Ghiorso in 1961 at Berkeley.  It was produced by bombarding 

californium with boron ions.  The name is temporary {IUPAC} nomenclature, 

the origin of the name comes from Ernest O.  Lawrence, the inventor of the 

cyclotron.  If sufficient amounts of lawrencium were produced, it would 

pose a radiation hazard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Lead">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Lead</rdfs:label>

<atomicNumber>82</atomicNumber>

<rdfs:comment>Heavy dull grey ductile metallic element, belongs to 

group 14.  Used in building construction, lead-place accumulators, bullets 

and shot, and is part of solder, pewter, bearing metals, type metals and 

fusible alloys.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Lithium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Lithium</rdfs:label>

<atomicNumber>3</atomicNumber>

<rdfs:comment>Socket silvery metal.  First member of group 1 of 

the periodic table.  Lithium salts are used in psychomedicine.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Lutetium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Lutetium</rdfs:label>

<atomicNumber>71</atomicNumber>

<rdfs:comment>Silvery-white rare-earth metal which is 

relatively stable in air.  It happens to be the most expensive rare-earth 

metal.  Its found with almost all rare-earth metals, but is very difficult 

to separate from other elements.  Least abundant of all natural elements.  

Used in metal alloys, and as a catalyst in various processes.  There are 

two natural, stable isotopes, and seven radioisotopes, the most stable 

being Lu-174 with a half-life of 3.3 years.  The separation of lutetium 

from {ytterbium} was described by Georges Urbain in 1907.  It was 

discovered at approximately the same time by Carl Auer von Welsbach.  The 

name comes from the Greek word lutetia which means Paris.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Magnesium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Magnesium</rdfs:label>

<atomicNumber>12</atomicNumber>

<rdfs:comment>Silvery metallic element belonging to group 2 of 

the periodic table (alkaline-earth metals).  It is essential for living 

organisms, and is used in a number of light alloys.  Chemically very 

reactive, it forms a protective oxide coating when exposed to air and 

burns with an intense white flame.  It also reacts with sulphur, nitrogen 

and the halogens.  First isolated by Bussy in 1828.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Manganese">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Manganese</rdfs:label>

<atomicNumber>25</atomicNumber>

<rdfs:comment>Grey brittle metallic transition element.  

Rather electropositive, combines with some non-metals when heated.  

Discovered in 1774 by Scheele.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Meitnerium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Meitnerium</rdfs:label>

<atomicNumber>109</atomicNumber>

<rdfs:comment>Half-life of approximately 5ms.  The creation 

of this element demonstrated that fusion techniques could indeed be used 

to make new, heavy nuclei.  Made and identified by physicists of the Heavy 

Ion Research Laboratory, Darmstadt, West Germany in 1982.  Named in honor 

of Lise Meitner the Austrian physicist.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Mendelevium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Mendelevium</rdfs:label>

<atomicNumber>101</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element.  

Belongs to the actinoid series.  Only known isotope, Md-256 has a 

half-life of 1.3 hours.  First identified by Glenn T.  Seaborg, Albert 

Ghiorso and associates in 1955.  Alternative name {unnilunium} has been 

proposed.  Named after the 'inventor' of the periodic table, Dmitri 

Mendeleev.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Mercury">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Mercury</rdfs:label>

<atomicNumber>80</atomicNumber>

<rdfs:comment>Heavy silvery liquid metallic element, belongs to 

the zinc group.  Used in thermometers, barometers and other scientific 

apparatus.  Less reactive than zinc and cadmium, does not displace 

hydrogen from acids.  Forms a number of complexes and organomercury 

compounds.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Molybdenum">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Molybdenum</rdfs:label>

<atomicNumber>42</atomicNumber>

<rdfs:comment>Silvery-white, hard metallic transition 

element.  It is chemically unreactive and is not affected by most acids.  

It oxidizes at high temperatures.  There are seven natural isotopes, and 

four radioisotopes, Mo-93 being the most stable with a half-life of 3500 

years.  Molybdenum is used in almost all high-strength steels, it has 

nuclear applications, and is a catalyst in petroleum refining.  Discovered 

in 1778 by Carl Welhelm Scheele of Sweden.  Impure metal was prepared in 

1782 by Peter Jacob Hjelm.  The name comes from the Greek word molybdos 

which means lead.  Trace amounts of molybdenum are required for all known 

forms of life.  All molybdenum compounds should be considered highly 

toxic, and will also cause severe birth defects.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Neodymium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Neodymium</rdfs:label>

<atomicNumber>60</atomicNumber>

<rdfs:comment>Soft bright silvery metallic element, belongs to 

the lanthanoids.  Seven natural isotopes, Nd-144 being the only 

radioactive one with a half-life of 10^10 to 10^15 years.  Six artificial 

radioisotopes have been produced.  The metal is used in glass works to 

color class a shade of violet-purple and make it dichroic.  One of the 

more reactive rare-earth metals, quickly reacts with air.  Used in some 

rare-earth alloys.  Neodymium is used to color the glass used in welder's 

glasses.  Neodymium is also used in very powerful, permanent magnets 

(Nd2Fe14B).  Discovered by Carl F.  Auer von Welsbach in Austria in 1885 

by separating didymium into its elemental components {praseodymium} and 

neodymium.  The name comes from the Greek words 'neos didymos' which means 

'new twin'.  Neodymium should be considered highly toxic, however evidence 

would seem to show that it acts as little more than a skin and eye 

irritant.  The dust however, presents a fire and explosion hazard.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Neon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Neon</rdfs:label>

<atomicNumber>10</atomicNumber>

<rdfs:comment>Colourless gaseous element of group 18 on the 

periodic table (noble gases).  Neon occurs in the atmosphere, and 

comprises 0.0018 percent of the volume of the atmosphere.  It has a 

distinct reddish glow when used in discharge tubes and neon based lamps.  

It forms almost no chemical compounds.  Neon was discovered in 1898 by Sir 

William Ramsey and M.W.  Travers.  </rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Neptunium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Neptunium</rdfs:label>

<atomicNumber>93</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element, 

belongs to the actinoids.  Np-237, the most stable isotope, has a 

half-life of 2.2*10^6 years and is a by product of nuclear reactors.  The 

other known isotopes have mass numbers 229 through 236, and 238 through 

241.  Np-236 has a half-life of 5*10^3 years.  First produced by Edwin M.  

McMillan and P.H.  Abelson in 1940.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Nickel">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Nickel</rdfs:label>

<atomicNumber>28</atomicNumber>

<rdfs:comment>Malleable ductile silvery metallic transition 

element.  Discovered by A.F.  Cronstedt in 1751.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Niobium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Niobium</rdfs:label>

<atomicNumber>41</atomicNumber>

<rdfs:comment>Soft, ductile grey-blue metallic transition 

element.  Used in special steels and in welded joints to increase 

strength.  Combines with halogens and oxidizes in air at 200 degrees 

celsius.  Discovered by Charles Hatchett in 1801 and isolated by 

Blomstrand in 1864.  Called {columbium} originally.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Nitrogen">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Nitrogen</rdfs:label>

<atomicNumber>7</atomicNumber>

<rdfs:comment>Colourless, gaseous element which belongs to 

group 15 of the periodic table.  Constitutes ~78 percent of the atmosphere 

and is an essential part of the ecosystem.  Nitrogen for industrial 

purposes is acquired by the fractional distillation of liquid air.  

Chemically inactive, reactive generally only at high temperatures or in 

electrical discharges.  It was discovered in 1772 by D.  Rutherford.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Nobelium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Nobelium</rdfs:label>

<atomicNumber>102</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element, belongs 

to the actinoids.  Seven known isotopes exist, the most stable being 

No-254 with a half-life of 255 seconds.  First identified with certainty 

by Albert Ghiorso and Glenn T.  Seaborg in 1966.  {Unnilbium} has been 

proposed as an alternative name.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Osmium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Osmium</rdfs:label>

<atomicNumber>76</atomicNumber>

<rdfs:comment>Hard blue-white metallic transition element.  Found 

with platinum and used in some alloys with platinum and iridium.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Oxygen">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Oxygen</rdfs:label>

<atomicNumber>8</atomicNumber>

<rdfs:comment>A colourless, odourless gaseous element belonging 

to group 16 of the periodic table.  It is the most abundant element 

present in the earth's crust.  It also makes up 20.8 percent of the 

Earth's atmosphere.  For industrial purposes, it is separated from liquid 

air by fractional distillation.  It is used in high temperature welding, 

and in breathing.  It commonly comes in the form of Oxygen, but is found 

as Ozone in the upper atmosphere.  It was discovered by Priestley in 

1774.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Palladium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Palladium</rdfs:label>

<atomicNumber>46</atomicNumber>

<rdfs:comment>Soft white ductile transition element.  Found 

with some copper and nickel ores.  Does not react with oxygen at normal 

temperatures.  Dissolves slowly in hydrochloric acid.  Discovered in 1803 

by W.H.  Wollaston.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Phosphorus">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Phosphorus</rdfs:label>

<atomicNumber>15</atomicNumber>

<rdfs:comment>Non-metallic element belonging to group 15 of 

the periodic table.  Has a multiple allotropic forms.  Essential element 

for living organisms.  It was discovered by Brandt in 1669.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Platinum">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Platinum</rdfs:label>

<atomicNumber>78</atomicNumber>

<rdfs:comment>Attractive greyish-white metal.  When pure, it is 

malleable and ductile.  Does not oxidize in air, insoluble in hydrochloric 

and nitric acid.  Corroded by halogens, cyandies, sulphur and alkalis.  

{Hydrogen} and {oxygen} react explosively in the presence of platinum.  

There are six stable isotopes and three radioisotopes, the most stable 

being Pt-193 with a half-life of 60 years.  Platinum is used in jewelry, 

laboratory equipment, electrical contacts, dentistry, and anti-pollution 

devices in cars.  PtCl2(NH3)2 is used to treat some forms of cancer.  

Platinum-{cobalt} alloys have magnetic properties.  It is also used in the 

definition of the Standard Hydrogen Electrode.  Discovered by Antonio de 

Ulloa in South America in 1735.  The name comes from the Spanish word 

platina which means silver.  Platinum metal is generally not a health 

concern due to its unreactivity, however platinum compounds should be 

considered highly toxic.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Plutonium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Plutonium</rdfs:label>

<atomicNumber>94</atomicNumber>

<rdfs:comment>Dense silvery radioactive metallic transuranic 

element, belongs to the actinoids.  Pu-244 is the most stable isotope with 

a half-life of 7.6*10^7 years.  Thirteen isotopes are known.  Pu-239 is 

the most important, it undergoes nuclear fission with slow neutrons and is 

hence important to nuclear weapons and reactors.  Plutonium production is 

monitored down to the gram to prevent military misuse.  First produced by 

Gleen T.  Seaborg, Edwin M.  McMillan, J.W.  Kennedy and A.C.  Wahl in 

1940.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Polonium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Polonium</rdfs:label>

<atomicNumber>84</atomicNumber>

<rdfs:comment>Rare radioactive metallic element, belongs to 

group 16 of the periodic table.  Over 30 known isotopes exist, the most of 

all elements.  Po-209 has a half-life of 103 years.  Possible uses in 

heating spacecraft.  Discovered by Marie Curie in 1898 in a sample of 

pitchblende.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Potassium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Potassium</rdfs:label>

<atomicNumber>19</atomicNumber>

<rdfs:comment>Soft silvery metallic element belonging to group 

1 of the periodic table (alkali metals).  Occurs naturally in seawater and 

a many minerals.  Highly reactive, chemically, it resembles sodium in its 

behavior and compounds.  Discovered by Sir Humphry Davy in 1807.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Praseodymium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Praseodymium</rdfs:label>

<atomicNumber>59</atomicNumber>

<rdfs:comment>Soft silvery metallic element, belongs to the 

lanthanoids.  Only natural isotope is Pr-141 which is not radioactive.  

Fourteen radioactive isotopes have been artificially produced.  Used in 

rare-earth alloys.  Discovered in 1885 by C.A. von Welsbach.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Promethium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Promethium</rdfs:label>

<atomicNumber>61</atomicNumber>

<rdfs:comment>Soft silvery metallic element, belongs to the 

lanthanoids.  Pm-147, the only natural isotope, is radioactive and has a 

half-life of 252 years.  Eighteen radioisotopes have been produced, but 

all have very short half-lives.  Found only in nuclear decay waste.  

Pm-147 is of interest as a beta-decay source, however Pm-146 and Pm-148 

have to be removed from it first, as they generate gamma radiation.  

Discovered by J.A.  Marinsky, L.E.  Glendenin and C.D.  Coryell in 

1947.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Protactinium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Protactinium</rdfs:label>

<atomicNumber>91</atomicNumber>

<rdfs:comment>Radioactive metallic element, belongs to the 

actinoids.  The most stable isotope, Pa-231 has a half-life of 2.43*10^4 

years.  At least 10 other radioactive isotopes are known.  No practical 

applications are known.  Discovered in 1917 by Lise Meitner and Otto 

Hahn.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Radium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Radium</rdfs:label>

<atomicNumber>88</atomicNumber>

<rdfs:comment>Radioactive metallic transuranic element, belongs 

to group 2 of the periodic table.  Most stable isotope, Ra-226 has a 

half-life of 1602 years, which decays into radon.  Isolated from 

pitchblende in 1898 Marie and Pierre Curie.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Radon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Radon</rdfs:label>

<atomicNumber>86</atomicNumber>

<rdfs:comment>Colorless radioactive gaseous element, belongs to 

the noble gases.  Of the twenty known isotopes, the most stable is Rn-222 

with a half-life of 3.8 days.  Formed by the radioactive decay of 

{Radium}-226.  Radon itself decays into {polonium}.  Used in radiotherapy.  

As a noble gas, it is effectively inert, though radon fluoride has been 

synthesized.  First isolated in 1908 by Ramsey and Gray.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Rhenium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Rhenium</rdfs:label>

<atomicNumber>75</atomicNumber>

<rdfs:comment>Silvery-white metallic transition element.  

Obtained as a by-product of molybdenum refinement.  Rhenium-molybdenum 

alloys are superconducting.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Rhodium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Rhodium</rdfs:label>

<atomicNumber>45</atomicNumber>

<rdfs:comment>Silvery white metallic transition element.  Found 

with platinum and used in some platinum alloys.  Not attacked by acids, 

dissolves only in aqua regia.  Discovered in 1803 by W.H.  Wollaston.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Rubidium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Rubidium</rdfs:label>

<atomicNumber>37</atomicNumber>

<rdfs:comment>Soft silvery metallic element, belongs to group 1 

of the periodic table.  Rb-97, the naturally occurring isotope, is 

radioactive.  It is highly reactive, with properties similar to other 

elements in group 1, like igniting spontaneously in air.  Discovered 

spectroscopically in 1861 by W.  Bunsen and G.R.  Kirchoff.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Ruthenium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Ruthenium</rdfs:label>

<atomicNumber>44</atomicNumber>

<rdfs:comment>Hard white metallic transition element.  Found 

with platinum, used as a catalyst in some platinum alloys.  Dissolves in 

fused alkalis, and is not attacked by acids.  Reacts with halogens and 

oxygen at high temperatures.  Isolated in 1844 by K.K.  Klaus.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Samarium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Samarium</rdfs:label>

<atomicNumber>62</atomicNumber>

<rdfs:comment>Soft silvery metallic element, belongs to the 

lanthanoids.  Seven natural isotopes, Sm-147 is the only radioisotope, and 

has a half-life of 2.5*10^11 years.  Used for making special alloys needed 

in the production of nuclear reactors.  Also used as a neutron absorber.  

Small quantities of samarium oxide is used in special optical glasses.  

The largest use of the element is its ferromagnetic alloy which produces 

permanent magnets that are five times stronger than magnets produced by 

any other material.  Discovered by Francois Lecoq de Boisbaudran in 

1879.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Scandium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Scandium</rdfs:label>

<atomicNumber>21</atomicNumber>

<rdfs:comment>Rare soft silvery metallic element belonging to 

group 3 of the periodic table.  There are ten isotopes, nine of which are 

radioactive and have short half-lives.  Predicted in 1869 by Mendeleev, 

isolated by Nilson in 1879.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Selenium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Selenium</rdfs:label>

<atomicNumber>34</atomicNumber>

<rdfs:comment>Metalloid element, belongs to group 16 of the 

periodic table.  Multiple allotropic forms exist.  Chemically resembles 

sulphur.  Discovered in 1817 by Jons J.  Berzelius.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Silicon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Silicon</rdfs:label>

<atomicNumber>14</atomicNumber>

<rdfs:comment>Metalloid element belonging to group 14 of the 

periodic table.  It is the second most abundant element in the Earth's 

crust, making up 25.7 percent of it by weight.  Chemically less reactive 

than carbon.  First identified by Lavoisier in 1787 and first isolated in 

1823 by Berzelius.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Silver">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Silver</rdfs:label>

<atomicNumber>47</atomicNumber>

<rdfs:comment>White lustrous soft metallic transition element.  

Found in both its elemental form and in minerals.  Used in jewellery, 

tableware and so on.  Less reactive than silver, chemically.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Sodium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Sodium</rdfs:label>

<atomicNumber>11</atomicNumber>

<rdfs:comment>Soft silvery reactive element belonging to group 1 

of the periodic table (alkali metals).  It is highly reactive, oxidizing 

in air and reacting violently with water, forcing it to be kept under oil.  

It was first isolated by Humphrey Davy in 1807.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Strontium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Strontium</rdfs:label>

<atomicNumber>38</atomicNumber>

<rdfs:comment>Soft yellowish metallic element, belongs to 

group 2 of the periodic table.  Highly reactive chemically.  Sr-90 is 

present in radioactive fallout and has a half-life of 28 years.  

Discovered in 1798 by Klaproth and Hope, isolated in 1808 by Humphry 

Davy.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Sulphur">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Sulphur</rdfs:label>

<atomicNumber>16</atomicNumber>

<rdfs:comment>Yellow, nonmetallic element belonging to group 16 

of the periodic table.  It is an essential element in living organisms, 

needed in the amino acids cysteine and methionine, and hence in many 

proteins.  Absorbed by plants from the soil as sulphate ion.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Tantalum">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Tantalum</rdfs:label>

<atomicNumber>73</atomicNumber>

<rdfs:comment>Heavy blue-grey metallic transition element.  

Ta-181 is a stable isotope, and Ta-180 is a radioactive isotope, with a 

half-life in excess of 10^7 years.  Used in surgery as it is unreactive.  

Forms a passive oxide layer in air.  Identified in 1802 by Ekeberg and 

isolated in 1820 by Jons J.  Berzelius.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Technetium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Technetium</rdfs:label>

<atomicNumber>43</atomicNumber>

<rdfs:comment>Radioactive metallic transition element.  Can 

be detected in some stars and the fission products of uranium.  First made 

by Perrier and Segre by bombarding molybdenum with deutrons, giving them 

Tc-97.  Tc-99 is the most stable isotope with a half-life of 2.6*10^6 

years.  Sixteen isotopes are known.  Organic technetium compounds are used 

in bone imaging.  Chemical properties are intermediate between rhenium and 

manganese.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Tellurium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Tellurium</rdfs:label>

<atomicNumber>52</atomicNumber>

<rdfs:comment>Silvery metalloid element of group 16.  Eight 

natural isotopes, nine radioactive isotopes.  Used in semiconductors and 

to a degree in some steels.  Chemistry is similar to {sulphur}.  

Discovered in 1782 by Franz Miller.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Terbium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Terbium</rdfs:label>

<atomicNumber>65</atomicNumber>

<rdfs:comment>Silvery metallic element belonging to the 

lanthanoids.  Tb-159 is the only stable isotope, there are seventeen 

artificial isotopes.  Discovered by G.G.  Mosander in 1843.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Thallium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Thallium</rdfs:label>

<atomicNumber>81</atomicNumber>

<rdfs:comment>Pure, unreacted thallium appears silvery-white 

and exhibits a metallic lustre.  Upon reacting with air, it begins to turn 

bluish-grey and looks like lead.  It is very malleable, and can be cut 

with a knife.  There are two stable isotopes, and four radioisotopes, 

Tl-204 being the most stable with a half-life of 3.78 years.  Thallium 

sulphate was used as a rodenticide.  Thallium sulphine's conductivity 

changes with exposure to infrared light, this gives it a use in infrared 

detectors.  Discovered by Sir William Crookes via spectroscopy.  Its name 

comes from the Greek word thallos, which means green twig.  Thallium and 

its compounds are toxic and can cause cancer.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Thorium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Thorium</rdfs:label>

<atomicNumber>90</atomicNumber>

<rdfs:comment>Grey radioactive metallic element.  Belongs to 

actinoids.  Found in monazite sand in Brazil, India and the US.  

Thorium-232 has a half-life of 1.39x10^10 years.  Can be used as a nuclear 

fuel for breeder reactors.  Thorium-232 captures slow {neutron}s and 

breeds uranium-233.  Discovered by Jons J.  Berzelius in 1829.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Thulium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Thulium</rdfs:label>

<atomicNumber>69</atomicNumber>

<rdfs:comment>Soft grey metallic element that belongs to the 

lanthanoids.  One natural isotope exists, Tm-169, and seventeen artificial 

isotopes have been produced.  No known uses for the element.  Discovered 

in 1879 by Per Theodor Cleve.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Tin">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Tin</rdfs:label>

<atomicNumber>50</atomicNumber>

<rdfs:comment>Silvery malleable metallic element belonging to group 

14 of the periodic table.  Twenty-six isotopes are known, five of which 

are radioactive.  Chemically reactive.  Combines directly with chlorine 

and oxygen and displaces hydrogen from dilute acids.  </rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Titanium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Titanium</rdfs:label>

<atomicNumber>22</atomicNumber>

<rdfs:comment>White metallic transition element.  Occurs in 

numerous minerals.  Used in strong, light corrosion-resistant alloys.  

Forms a passive oxide coating when exposed to air.  First discovered by 

Gregor in 1789.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Tungsten">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Tungsten</rdfs:label>

<atomicNumber>74</atomicNumber>

<rdfs:comment>White or grey metallic transition element, 

formerly called {wolfram}.  Forms a protective oxide in air and can be 

oxidized at high temperature.  First isolated by Jose and Fausto de 

Elhuyer in 1783.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unnildecium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unnildecium</rdfs:label>

<atomicNumber>110</atomicNumber>

<rdfs:comment>Half-life of approximately 10ms.  Reported in 

1994 by German researchers at Darmstadt, Germany.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unnilhexium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unnilhexium</rdfs:label>

<atomicNumber>106</atomicNumber>

<rdfs:comment>Half-life of 0.9 +/- 0.2 s.  Discovered by the 

Joint Institute for Nuclear Research at Dubna (U.S.S.R.) in June of 1974.  

Its existence was confirmed by the Lawrence Berkeley Laboratory and 

Livermore National Laboratory in September of 1974.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unniloctium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unniloctium</rdfs:label>

<atomicNumber>108</atomicNumber>

<rdfs:comment>Radioactive transition metal.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unnilpentium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unnilpentium</rdfs:label>

<atomicNumber>105</atomicNumber>

<rdfs:comment>Radioactive transactinide element.  Half-life 

of 1.6s.  Discovered in 1970 by Berkeley researchers.  So far, seven 

isotopes have been discovered.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unnilquadium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unnilquadium</rdfs:label>

<atomicNumber>104</atomicNumber>

<rdfs:comment>Radioactive transactinide element.  Expected 

to have similar chemical properties to those displayed by hafnium.  Rf-260 

was discovered by the Joint Nuclear Research Institute at Dubna (U.S.S.R.) 

in 1964.  Researchers at Berkeley discovered Unq-257 and Unq-258 in 

1964.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Unnilseptium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Unnilseptium</rdfs:label>

<atomicNumber>107</atomicNumber>

<rdfs:comment>Radioactive transition metal.  Half-life of 

approximately 1/500 s.  Discovered by the Joint Institute for Nuclear 

Research at Dubna (U.S.S.R.) in 1976.  Confirmed by West German physicists 

at the Heavy Ion Research Laboratory at Darmstadt.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Uranium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Uranium</rdfs:label>

<atomicNumber>92</atomicNumber>

<rdfs:comment>White radioactive metallic element belonging to 

the actinoids.  Three natural isotopes, U-238, U-235 and U-234.  

Uranium-235 is used as the fuel for nuclear reactors and weapons.  

Discovered by Martin H.  Klaproth in 1789.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Vanadium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Vanadium</rdfs:label>

<atomicNumber>23</atomicNumber>

<rdfs:comment>Soft and ductile, bright white metal.  Good 

resistance to corrosion by alkalis, sulphuric and hydrochloric acid.  It 

oxidizes readily about 933K.  There are two naturally occurring isotopes 

of vanadium, and 5 radioisotopes, V-49 having the longest half-life at 337 

days.  Vanadium has nuclear applications, the foil is used in cladding 

titanium to steel, and vanadium-gallium tape is used to produce a 

superconductive magnet.  Originally discovered by Andres Manuel del Rio of 

Mexico City in 1801.  His discovery went unheeded, however, and in 1820, 

Nils Gabriel Sefstron of Sweden rediscovered it.  Metallic vanadium was 

isolated by Henry Enfield Roscoe in 1867.  The name vanadium comes from 

{Vanadis}, a goddess of Scandinavian mythology.  Silvery-white metallic 

transition element.  Vanadium is essential to {ascidian}s.  Rats and 

chickens are also known to require it.  Metal powder is a fire hazard, and 

vanadium compounds should be considered highly toxic.  May cause lung 

cancer if inhaled.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Xenon">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Xenon</rdfs:label>

<atomicNumber>54</atomicNumber>

<rdfs:comment>Colourless, odourless gas belonging to group 18 on 

the periodic table (the noble gases.) Nine natural isotopes and seven 

radioactive isotopes are known.  Xenon was part of the first noble-gas 

compound synthesized.  Several others involving Xenon have been found 

since then.  Xenon was discovered by Ramsey and Travers in 1898.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Ytterbium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Ytterbium</rdfs:label>

<atomicNumber>70</atomicNumber>

<rdfs:comment>Silvery metallic element of the lanthanoids.  

Seven natural isotopes and ten artificial isotopes are known.  Used in 

certain steels.  Discovered by J.D.G.  Marignac in 1878.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Yttrium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Yttrium</rdfs:label>

<atomicNumber>39</atomicNumber>

<rdfs:comment>Silvery-grey metallic element of group 3 on the 

periodic table.  Found in uranium ores.  The only natural isotope is Y-89, 

there are 14 other artificial isotopes.  Chemically resembles the 

lanthanoids.  Stable in the air below 400 degrees, celsius.  Discovered in 

1828 by Friedrich Wohler.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Zinc">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Zinc</rdfs:label>

<atomicNumber>30</atomicNumber>

<rdfs:comment>Blue-white metallic element.  Occurs in multiple 

compounds naturally.  Five stable isotopes are six radioactive isotopes 

have been found.  Chemically a reactive metal, combines with oxygen and 

other non-metals, reacts with dilute acids to release hydrogen.</rdfs:comment>

</rdfs:Class>



<rdfs:Class rdf:ID= "Zirconium">

<rdfs:subClassOf rdf:resource ="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:label>Zirconium</rdfs:label>

<atomicNumber>40</atomicNumber>

<rdfs:comment>Grey-white metallic transition element.  Five 

natural isotopes and six radioactive isotopes are known.  Used in nuclear 

reactors for a {neutron} absorber.  Discovered in 1789 by Martin Klaproth, 

isolated in 1824 by Berzelius.</rdfs:comment>

</rdfs:Class>



<owl:DatatypeProperty  rdf:ID= "atomicNumber">

<rdfs:comment>(atomicNumber ?ELEMENT ?NUMBER) means that 

the ElementalSubstance ?ELEMENT has the atomic number ?NUMBER.  The 

atomic number is the number of Protons in the nucleus of an Atom.</rdfs:comment>

<rdf:type rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#BinaryPredicate"/>

<rdf:type rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#AsymmetricRelation"/>

<rdfs:domain rdf:resource="http://reliant.teknowledge.com/DAML/SUMO.owl#ElementalSubstance"/>

<rdfs:range rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#PositiveInteger"/>

</owl:DatatypeProperty>



<owl:ObjectProperty   rdf:ID= "boilingPoint">

<rdfs:comment>(boilingPoint ?TYPE ?TEMP) means that 

the temperature at which the PureSubstance ?TYPE changes state from a 

Liquid to a Gas is ?TEMP.</rdfs:comment>

<rdf:type rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#BinaryPredicate"/>

<rdfs:domain rdf:resource="http://reliant.teknowledge.com/DAML/SUMO.owl#PureSubstance"/>

<rdfs:range rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#TemperatureMeasure"/>

</owl:ObjectProperty>



<owl:ObjectProperty   rdf:ID= "meltingPoint">

<rdfs:comment>(meltingPoint ?TYPE ?TEMP) means that the 

temperature at which the PureSubstance ?TYPE changes state from a Solid 

to a Liquid is ?TEMP.  Note that Arsenic can sublimate directly from 

Solid to Gas, which means that its melting and boiling points are equal.</rdfs:comment>

<rdf:type rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#BinaryPredicate"/>

<rdfs:domain rdf:resource="http://reliant.teknowledge.com/DAML/SUMO.owl#PureSubstance"/>

<rdfs:range rdf:resource = "http://reliant.teknowledge.com/DAML/SUMO.owl#TemperatureMeasure"/>

</owl:ObjectProperty>





</rdf:RDF>
