N₂ was discovered by Daniel Rutherford. It is the first member of group 15 in the periodic table.

Occurrence of nitrogen : N₂ , occurs both in the free state as well as in the combined state. N₂ occurs in atmosphere to the extent of 78% by volume in free state. N₂ is present in many compounds such as potassium nitrate (nitre). Sodium nitrate (Chile salt peter) and many ammonium compounds. N₂ is an important constituent of proteins in plants and animals in combined state.

Preparation : It is prepared by the following methods,

(1) Laboratory method of preparation of nitrogen: In the laboratory N₂ is prepared by heating an aqueous solution containing an equivalent amounts of NH₄CI and NaNO₂ .

(2) Commercial preparation of nitrogen: Commercially N₂ is prepared by the fractional distillation of liquid air.