ARGON

• Atomic Number: 18
• Atomic Symbol: Ar
• Atomic Weight: 39.948
• Electron Configuration: 2-8-8

---

History:

(Gr. argos, inactive) Its presence in air was suspected by Cavendish in 1785, discovered by Lord Rayleigh and Sir William Ramsay in 1894. The gas is prepared by fractionation of liquid air, the atmosphere containing 0.94% argon. The atmosphere of Mars Argon is considered to be a very inert gas and is not known to form true chemical compounds, as do kypton, xenon, and radon. Naturally occurring argon is a mixture of three isotopes. Twelve other radioactive isotopes are known to exist.

Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond