The Total solution for NCERT class 6-12
Nitrogen exists as diatomicmolecule and phosphorus as P4. Why?
Nitrogen owing to its small sizehas a tendency to form pπ−pπ multiple bonds withitself. Nitrogen thus forms a very stable diatomic molecule, N2. Onmoving down a group, the tendency to form pπ−pπ bondsdecreases (because of the large size of heavier elements). Therefore,phosphorus (like other heavier metals) exists in the P4 state.