Inert gas

gas which does not undergo chemical reactions under a set of given conditions

An inert gas is a gas that does not usually react chemically with other things. Examples of inert gases are nitrogen (N2) and helium.

An inert gas made of separate atoms of one element is called a noble gas. Inert gases can also be made of more than one atom together. They can be gases of molecules or mixtures of gases of elements.

Inert gases are used in several ways. A gas made from nitrogen is used to keep vegetables from spoiling when they are transported. Other inert gases are used in welding. They are put into gasoline tanks to help prevent explosions.