Which gives +7 oxidation state ?

Options

A. Mn(25)
B. Cr(24)
C. Cu(29)
D. Fe(26)

Answer

A

Explanation

For d-block elements,
oxidation state=ns electron+(n-1)d electrons (unpaired)
(a) `Mn(25)=[Ar]3d^(5)4s^(2),O.S.=5+2=7`
(b) `Cr(24)=[Ar]3d^(5)4s^(1),O.S.=5+1=6`
`(c ) Cu(29)=[Ar]3d^(10)4s^(1),O.S.=0+1=1`
(d)` Fe(25)=[Ar]3d^(6)4s^(2),O.S.=+2 and +3`
Thus , only Mn exhibits `+7` oxidation state among the given elements .