Arrange `S, P` and `As` in order of increasing ionisation energy.

Options

A. `S lt P lt As`
B. `P lt S lt As`
C. `As lt S lt P`
D. `As lt P lt S`

Answer

C

Explanation

`P = 1s^2, 2s^2 2p^6, 3s^2 3p^3` half filled orbital
As ` = [Ar] 4s^2 4p^3`
`S = 1s^2 2s^2 2p^6, 3s^2 3p^4`
Hence ionization energy order
`{P gt S gt As}`.