Which of the following has highest second ionization energy ?

Options

A. Ni
B. V
C. Cr
D. Mn

Answer

C

Explanation

Electronic configuration for chromium is :
`""_(24)Cr to 1 s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(5)4s^(1)`
After ionisation of 4s elecgron the next electron which will be ionised is from 3d orbital . As `3d^(5)` electronic configuration, therefore is stable. Hence, the second ionisation of Cr will require much greater ionisation energy than the expected one.