The number of d-electrons in `Fe^(2+)`(Z=26) is not equal to the number of electrons in which one of the following ?

Options

A. d-electrons in Fe (Z = 26)
B. p-electrons in Ne (Z = 10)
C. s-electrons in Mg (Z = 12)
D. p-electrons in Cl (Z = 17)

Answer

D

Explanation

`._(26)Fe = 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(6) 4s^(2)` (d - electrons = 6)
`Fe^(2+) = 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(6)` (d-electrons = 6)
`._(10)Ne = 1s^(2) 2s^(2) 2p^(6)` (p-electrons = 6)
`._(12)Mg = 1s^(2) 2s^(2) 2p^(6) 3s^(2)` (s-electron `= 2 + 2 + 2 = 6`)
`._(17)Cl = 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(5)` (p-electrons `= 6 + 5 = 11`)