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|Atomic Number:||18||Atomic Symbol:||Ar|
|Atomic Weight:||39.948||Electron Configuration:||2-8-8|
|Melting Point:||-189.3oC||Boiling Point:||-186oC|
|Uses:||light bulbs and other uses for non-reactive gases|
History(Gr. argos, inactive) Its presence in air was suspected by
Cavendish in 1785, discovered by Lord Rayleigh and Sir William Ramsay in 1894.
SourcesThe gas is prepared by fractionation of liquid air because the
atmosphere contains 0.94% argon. The atmosphere of Mars contains 1.6% of 40Ar
and 5 p.p.m. of 36Ar.
PropertiesArgon is two and one half times as soluable in water as
nitrogen, having about bhe same solubility as oxygen. Argon is colorless and
odorless, both as a gas and liquid. Argon is considered to be a very inert gas
and is not known to form true chemical compounds, as do kypton, xenon, and
IsotopesNaturally occurring argon is a mixture of three isotopes.
Twelve other radioactive isotopes are known to exist.
UsesIt is used in electric light bulbs and in fluorescent tubes at a
pressure of about 400 Pa. and in filling photo tubes, glow tubes, etc. Argon is
also used as an inert gas shield for arc welding and cutting, as blanket for the
production of titanium and o ther reactive elements, and as a protective
atmosphere for growing silicon and germanium crystals.