Covalent bond.
<P>
   Each  hydrogen  atom has a single electron (represented as a cloud) in
   its valence shell - shell #1.
   The two valence electrons be shared in a strong covalent bond, forming
   an H[2] molecule.
   In  the  resulting  molecule, the shared pair of electrons enable each
   atom to complete its valence shell.
<P>
   Two  pairs  of  valence  electrons can also be shared to form a double
   covalent bond.
<P>
   Review:  <A ClAsS=ACT Href="http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?2&amp;D" oNClick="popact('http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?2&amp;D');txtcolor('covalent2','gray');return false;" Id=covalent2><iMg sRc="/images/tutorial.gif" aLt='' boRDer=0></A>