Answer: (2) NCl5
- Nitrogen does not have d orbitals to expand its covalence beyond four.
- Since phosphorus and arsenic have d-orbitals, they can accept electrons from five Cl atoms.
- The d-orbitals are absent in N, so electrons can only be accommodated in the p-orbitals of 5 Cl atoms. As a result, NCl5 does not exist.