N and Bi do not form pentachlorides but P does- why?

Explanation

Due to absence of d-orbitals in nitrogen `(1s^(2)2s^(2)2p^(3))`, its 2s electron cannot be excited ta create five half-filled orbitals necessary for the five N- Cl bonds. Hence, nitrogen does not form `NCl_(5)` . In contrast, Bi is expected to form pentachloride because it has vacant 6d -orbitals to which one 6s -electron can be excited to make me half-filled orbitals required for five Bi - Cl bonds. However due to inert pair effect, the energy needed for excitation of 6s -electron to 6d -orbital is much higher and in fact, much more than the energy released when two additional Bi - Cl bonds are formed. Thus, Bi does not form `BiCl_(5)` . Phosphorus has vacant d -orbitals in its valence shell and due to strong screening effect of s -and p -electrons of the inner orbitals, 3s electron can easily be excited to have five half-filled orbitals needed for the formation of five P - CI bonds. Thus, phosphorus forms `PCl_(5)` easily.