noble gases

Family of chemical elements also called inert, as they are weakly reactant.

radon

Highly radioactive noble gas that is used mainly in medicine (destroying cancerous tumors) and in predicting earthquakes.

xenon

Rarest gas in the atmosphere; it is used mainly in discharge lamps, photoflash bulbs and lasers.

krypton

Noble gas that is used in some incandescent lamps and in photography.

argon

Most abundant of the noble gases; it is used especially in incandescent lamps and in welding (protective gas).

neon

Noble gas that is used mainly in lighting (billboards, television tubes and fog lamps), but also as a liquid coolant.

helium

The lightest of the noble gases is noncombustible and abundant in the stars; it is used especially in inflating aerostats (such as balloons and dirigibles).