Argon

Argon
Properties
Atomic symbol	Ar
Atomic number	18
Classification	Non-metal
Atomic mass	39.9 amu
Other Information
Date of discovery	1894
Name of discoverer	Sir William Ramsey
Name origin	From the Greek argon.
Uses	Lighting
Obtained from	Air

Argon (Ar) is the most common of the noble gases. It is an inert component which comprises 0.934% of the Earth's atmosphere. It is a common shielding agent in welding or melting of metal, preventing reaction and subsequent oxidation of the hot metal with atmospheric air.