Two elements in I transition series have four unparired electrons in their `+2` states . Thers are :

Options

A. `Cr, Mn`
B. Mn. Fe
C. Cr, Fe
D. `Fe, Ni`

Answer

C

Explanation

`Cr : 1s^2 , 2as^2 2p^6 , 3s^26 3d^5 , 4s^1`,
`Cr^(2+) : 1s^2 , 2as^2 2p^6 , 3s^26 3d^6 , 4s^2`,
`Fe : 1s^2 , 2as^2 2p^6 , 3s^26 3d^6 , 4s^4` `4s^2,`
`Fe^(2+) : 1s^2 , 2as^2 2p^6 , 3s^26,`,