Atomic Number 18     Atomic Mass 39.948      State gas     Color colorless

Melting Point  -189.2°C     Boiling Point  -185.7°C    

Natural Isotopes Ar-36 0.337% Ar-38 0.063% Ar-40 99.600%     

Abbreviated Electron Configuration [Ne] 3s² 3p⁶

Discovered by Rayleigh and Ramsay in 1894.