CHEMystery: The Periodic Table of the Elements

<BODY BGCOLOR=#000000 TEXT=#FFFFFF LINK=#FF7F00 VLINK=#00CFCF ALINK=#FFFF00> <B><SMALL> <A HREF=".." TARGET="_parent">Return</A> to the Main CHEMystery Page.<BR> <A HREF="../pertable" TARGET="_parent">Return</A> to the Periodic Table of the Elements<BR> </SMALL></B> <H1><FONT FACE="Arial"><I>Element 2 - Helium (He) <A HREF="2.wav"><IMG SRC="sound.gif" ALT="sound" BORDER=0 ALIGN=top></A></I></FONT></H1> From <I>helios</I>, or sun; discovered in 1868. Almost all the helium in the world comes from natural gas wells in the United States. One well in Arizona produces a gas that is 8 per cent helium. Lighter than air, it is widely used in blimps and balloons in place of highly flammable hydrogen. <HR> <CENTER><TABLE BORDER=1 CELLPADDING=2 CELLSPACING=2> <TR><TD COLSPAN=2><CENTER><H3><FONT FACE="Arial">Properties</FONT></H3></CENTER></TD></TR> <TR> <TD><A HREF="../reference/glossary.html#atomicnumber" TARGET="_parent">Atomic Number</A>:</TD> <TD>2<BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#atomicweight" TARGET="_parent">Atomic Weight</A>:</TD> <TD>4.00260<BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#electronconfiguration" TARGET="_parent">Electron Configuration</A> (at ground state):</TD> <TD>1s<SUP>2</SUP><BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#oxidationstate" TARGET="_parent">Oxidation States</A> (Bold most stable):</TD> <TD><B>0</B><BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#boilingpoint" TARGET="_parent">Boiling Point</A> (K):</TD> <TD>4.216<BR></TD> </TR> <TR> <TD>Melting Point (K):</TD> <TD>0.95<BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#density" TARGET="_parent">Density</A> (at <A HREF="../reference/glossary.html#standardconditionsoftemperatureandpressure">STP</A> -- g/l):</TD> <TD>0.1785<BR></TD> </TR> <TR> <TD>Atomic Volume (liquid state at boiling point -- cm<SUP>3</SUP>/mol) <TD>31.80<BR></TD> </TR> <TR> <TD>Number of stable <A HREF="../reference/glossary.html#isotopes" TARGET="_parent">isotopes</A>:</TD> <TD>2<BR></TD> </TR> <TR> <TD>Covalent Radius (Å):</TD> <TD>0.93<BR></TD> </TR> <TR> <TD>First <A HREF="../reference/glossary.html#ionizationenergy" TARGET="_parent">Ionization Potential</A> (V):</TD> <TD>24.587<BR></TD> </TR> <TR> <TD><A HREF="../reference/glossary.html#specificheat" TARGET="_parent">Specific Heat</A> Capacity (at 300K -- J g<SUP>-1</SUP> K<SUP>-1</SUP>):</TD> <TD>5.193<BR></TD> </TR> <TR> <TD>Heat of Vaporization (kJ/mol):</TD> <TD>0.084<BR></TD> </TR> <TR> <TD>Heat of Fusion (kJ/mol):</TD> <TD>0.021<BR></TD> </TR> <TR> <TD>Thermal Conductivity (at 300K -- W m<SUP>-1</SUP> K<SUP>-1</SUP>):</TD> <TD>0.152<BR></TD> </TR> <TR> <TD>Crystal Structure:</TD> <TD><IMG SRC="hexagonal.gif" ALIGN=middle> Hexagonal<BR></TD> </TR> </TABLE></CENTER> <HR> <CENTER> <A HREF="ptbl_bar.map"><IMG SRC="ptbl_bar.gif" ALT="The Periodic Table of the Elements" BORDER=0 WIDTH=579 HEIGHT=49 ISMAP></A> </CENTER> </BODY>