In which of the following oxoanions the oxidation state of central atom is not same as that of its group number in periodic table ?

Options

A. `MnO_4^(-)`
B. `Cr_2O_7^(2-)`
C. `VO_4^(3-)`
D. `FeO_4^(2-)`

Answer

D

Explanation

(A)`MnO_4^(-)=+7, [Ar]^(18)3d^(5)4s^(2)=7`
(B)`Cr_2O_7^(2-)=+6, [Ar]^(18)3d^(5)4s^(1)=6`
(C )`VO_4^(3-)=+5, [Ar]^(18)3d^(3)4s^(2)=5`
(D)`FeO_4^(2-)=+6, [Ar]^(18)3d^(6)4s^(2)=8`