Xenon is one of the "noble" gases, also known as "rare" or "inert" gases. They are uncommon and highly unreactive. The six inert gases make up about one oercent of Earth's atmosphere, and are thought to have been released into the air as a byproduct of the decay of radioactive elements. They are all monatomic in structure, which means a molecule consists of only one atom. The outer layer of the atoms of all six inert gases consist of eight electrons, which is quite stable. This impedes the loss or gain of electrons, which explains the nonreactivity of these gases. Xenon's Atomic Number is 54, Atomic Weight is 131.30, and its symbol is Xe.
Xenon is the rarest, and was first discovered in 1898 by William Ramsey and Morris Travers. It is odorless, colorless and tasteless, and is used in the manufacture of specialized lamps and tubes, such as vacuum tubes and bacterial lamps. Xenon is found in nature in nine stable isotopes. In 1962 Neil Bartlett created the first compound containing an inert gas, using xenon.