Name: argon	Group number: 18
Symbol: Ar	Group name: Noble gas
Atomic number: 18	Period number: 3
Atomic weight: 39.948 (1) g r	Block: p-block
CAS Registry ID: 7440-37-1	Voice:
Standard state: gas at 298 K	Colour: colourless
Classification: Non-metallic	Availability:

Argon is colourless and odourless. Argon is very inert and is not known to form true chemical compounds. It makes a good atmosphere for working with air-sensitive materials since it is heavier than air and less reactive than N₂.

Isolation

Argon is present to a small extent in the atmosphere and is obtained as a byproduct from the liquefaction and separation of air. This would not normally be carried out in the laboratory and argon is available commercially in cylinders at high pressure.