Question

PCl5 is known but NCl5 is not known give reason

Answer 1

P has d orbitals so it can form 5 bonds but N lacks d orbitals so it cannot form more than 4 bonds.

Answer 2

Phosphorous has d-orbitals & hence

can accommodate the electrons

from Cl into them,in case of N the

d-orbitals are absent & electrons can be

accommodated only in p-orbitals.Hence

PC15 exists.