Atomic Number: 2 Atomic Mass: 4.003

Helium is a colourless, odourless, non-toxic Noble gas. It is a very highly unreactive gas.

It has the lowest density of all the gases.

A mixture of helium and oxygen is used as an artifical atmosphere for deep sea divers.

Helium is also used to detect leaks and to inflate car airbags after impact.

Uses: cooling medium for Large Hadron Collidor, baloons, airships, fibreoptics.