Key information
Atomic number: 
7
Atomic weight: 
14.01
Density: 
810 kg/m³
Boiling point: 
77.36° K
Melting point: 
63.16° K
Heat vapour: 
2.79 kJ/mol
Heat fusion: 
0.36 kJ/mol

Nitrogen is the element in greatest abundance in air (78.082% by volume of dry air). It forms strong bonds with other atoms which are difficult to split. Nitrogen atoms in N2 are bonded together by a triple bond, and are less reactive than oxygen, the other main component of air: nitrogen does not react readily unless it is heated to high temperatures or is provided with a catalyst.
By the late 18th Century the study of chemistry had advanced to the stage that it was known that a fraction of air did not support combustion. An early description of nitrogen is contained within Karl Wilhelm Scheele's Chemische Abhandlung von der Luft und dem Feuer (Chemical treatise of Air and Fire) first published in 1777. In a paper published in 1785, the English chemist Henry Cavendish (1731-1810), proved the correction of the supposition that when electric sparks are passed through air there is a shrinkage of volume owing to the nitrogen uniting with oxygen to form nitric acid. Antoine Laurent Lavoisier (1743-1794) named nitrogen azote.
Nitrogen, at -196°c, can freeze liquids, and it is used to freeze food and biological material in order to preserve them. As nitrogen gas is an unreactive atmosphere it is used in petrol storage tanks and food packaging to slow down rates of reaction.

Electron Shell: 
Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages