Argon is monatomic, colourless, odourless, tasteless and
nontoxic gas. Together with helium, neon, krypton, xenon, and
radon, it constitutes a special group of gases known as the
rare, noble or inert gases.
Argon is present in the atmosphere at a concentration of 0.934% by volume at the earth’s surface. Air is the only known source for the production of pure argon.
Argon is the most commonly occurring of the rare gases.