Rare Gases

The rare gases form group 18 of the periodic table of elements. This is the vertical column of elements on the extreme right of the Periodic table. As with other groups of elements, the placement of all the rare gases in the same group reflects their similar properties. The rare gases are all colorless, odorless, and tasteless. They are also monatomic gases which means that they exist as individual atoms.

The most noticeable feature of the rare gases is their lack of chemical reactivity. Helium, neon, and argon do not combine with any other atoms to form compounds, and it has been only in the last few decades that compounds of the other rare gases have been prepared. In 1962 Neil Bartlett (1932-), then at the University of British Columbia, succeeded in the historic preparation of the first compound of xenon. Since then, many xenon compounds containing mostly fluorine or oxygen atoms have also been prepared. Krypton and radon have also been combined with fluorine to form simple compounds. Because some rare gas compounds have powerful oxidizing properties (they can remove electrons from other substances) they have been used to synthesize other compounds.

The low reactivity of the rare gases is due to the arrangement of electrons in the rare gas atoms. The configuration of electrons in these elements makes them very stable and therefore unreactive. The reactivity of any element is due, in part, to how easily it gains or loses electrons, which is necessary for an atom to react with other atoms. The rare gases do not readily do either. Prior to Bartlett's preparation of the first xenon compound, the rare gases were widely referred to as the inert gases. Because the rare gases are so unreactive, they are harmless to living organisms. Radon, however, is hazardous because it is radioactive.