Question

Explain how does nitrogen exhibit anomalous behaviour amongst group 15 elements.

Answer 1

Nitrogen shows anomalous behaviour as follows:-

1. Nitrogen is a gas, whereas the other members of the family are solids.
2. Nitrogen is diatomic, while the other elements such as phosphorus and arsenic form tetra-atomic molecules (P₄, As₄).
3. Nitrogen forms five types of oxides (N₂O, NO, N₂O₃, N₂O₄ and N₂O₅), while the other members form two types of oxides—trioxides and pentoxides.
4. Hydrides of nitrogen consist of H-bonding, which is absent in members of other elements.
5. Nitrogen does not show penta-covalency because of the absence of d-orbitals, but all other elements show penta-covalency.
6. Nitrogen dose not form complexes because of the absence of d-orbitals, while the other elements show complex formation (e.g. [PCl₆]^-, [AsCl₆]^-).
7. The hydride of nitrogen (NH₃) is highly basic in nature, whereas the hydrides of other elements are slightly basic.