The number of unpaired electrons in the complex ion `[CoF_(6)]^(3-)` is

Options

A. 3
B. 2
C. 4
D. 0

Answer

C

Explanation

In complex ion `[CoF_(6)]^(3-)`, Co is present in + 3 oxidation state
`""_(27)Co=1s^(2),2s^(2)2p^(6),3s^(2)3p^(6)3d^(7),4s^(2)`
`Co^(3+)=1s^(2),2s^(2)2p^(6),3s^(2)3p^(6)3d^(6)`
Therefore, the number of unpaired electrons in 3d subshell of `[CoF_(6)]^(3-)` is 4.