The number of d-electron retained in `Fe^(2) ("At no. of" Fe =26)` ion is.

Options

A. `6`
B. `5`
C. `4`
D. `3`

Answer

A

Explanation

`(Z = 26): 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(6)4s^(2)` or simply `[Ar] 3d^(6)4s^(2)`. Thus, the ground state electron configuration of `Fe^(2+)` will be `[Ar]3d^(6)`. Therfore, it retains `6d` electrons. Never write the configuration as `[Ar]4s^(2)3d^(6)` because we many make the mistake of ionizing `3d`electrons first leaving behind just four `d` electrons.