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1.                 From The Elements (07Nov00):
                   
   
   
                   
                     
   xenon
   Symbol: Xe
   Atomic number: 54
   Atomic weight: 131.30
   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.