Atomic Number: 54
Atomic Mass: 131.29 amu (atomic mass units)
Melting Point: minus 111.9 C (161.25 K, minus 169.42 F)
Boiling Point: minus 108.1 C (165.05 K, minus 162.58 F)
Number of Protons: 54
Number of Electrons: 54
Number of Neutrons: 77
Classification: Noble Gas
Crystal Structure: Cubic
Density @ 293 K: 0.0058971 grams per cubic centimeter
Xenon was discovered by the British chemists Sir William Ramsay and Morris M. Travers on July 12 1898. These scientists had recently discovered two other elements, the noble gases neon and krypton. They discovered all three gases through their studies of liquefied air. Their experimental procedure involved the evaporation of large quantities of the liquid air and examination of the residue. The large amount of liquid air was needed for its discovery as the Earths' atmosphere contains only 0.87 parts per million of the gas. The name xenon comes from the Greek for stranger and is pronounced zee-non.
Until the early sixties it was thought that the noble gases were completely inert and unable to form any compounds. It has now been found that xenon can form compounds with a number of other elements. The most common compounds are formed with the elements fluorine, platinum and oxygen. Xenon trioxide has been found to be highly explosive. It is possible to produce xenon metal by subjecting the element to several hundred kilobars of pressure.
Xenon has nine naturally occurring isotopes. The most common of these natural isotopes are xenon-129 and xenon-132 together these two isotopes account for more than half of the xenon in the atmosphere. Seven of the natural isotopes are stable while the other two have extremely long half lives. It also has about thirty man-made unstable isotopes with half lives ranging from about 150 nanoseconds to 11.934 days.
Xenon within a vacuum tube will glow when excited by an electrical charge. This ability has enabled its use in a number of lamps. Xenon lamps are used to produce strobe effects, bactericidal lamps and to excite ruby lasers.
Its high molecular weight has lent to it being used within the field of atomic physics. The element has proved valuable in bubble chambers and probes within this field.
The space probe Deep-Space-1 used xenon ions to power its experimental ion drive engine. This experimental but successful space probe was launched on 24 October 1998 and retired on 18 December 2001.
Perxenate compounds are used within the field of analytical chemistry as oxidizing agents.