Nitrogen

Nitrogen

Nitrogen was discovered by Daniel Rutherford in 1772. It is the first member of group 15 of the periodic table. It has the electronic configuration      and therefore has five electrons in its valence shell. In the molecular form, it exists as a diatomic a=molecule (N2) having triple bond between nitrogen atoms (N=N). Therefore, it is also referred to as dinitrogen. It is a typical non-metal with high electronegatively next only to fluorine and oxygen.

Terrestrial Abundance and Distribution

Despite its ready availability in the atmosphere, nitrogen is relatively less abundant in the crustal rocks and soils of the earth. Dinitrogen occurs both in the free state as well as in the combined state.

(i)                  In free state:

Nitrogen occurs in the atmosphere to the extent of 78% by volume. It is also present in the volcanic gases evolved by the burning of coal.

(ii)                 In combined state:

Nitrogen is present in many compounds such as sodium nitrate (chile salt peter), potassium nitrate, KNO3 (nitre or Indian saltpeter) and many ammonium compounds. Nitrogen is an important constituent of proteins in plants and animals.

Its abundance in earth including the atmosphere is 0.01% by weight.