Explain why both N and Bi do not form pentahalides while phosphorus does.

Explanation

Both N and Bi donot form pentahalides but due to different reasons. The element N cannot extend its covalency to five due to the absence of vacant 2d orbitals in the valence shell. The element Bi does not form pentahalide due to strong inert pair effect by the valence 6s electrons which are not available for bonding. The element P does form pentahalides `(PCl_(5))` due to the availability of 3d orbitals which can participate in the bond formation.