The number of d-electrons in Fe²⁺(Z=26) is not equal to the number of electrons in which one of the following

Options

(a) p-electrons in Cl(Z=17)
(b) d-electrons in Fe(Z=26)
(c) p-electrons in Ne(Z=10)
(d) s-electrons in Mg(Z=12)

Correct Answer:

p-electrons in Cl(Z=17)

Explanation:

Fe⁺²=3d⁶(number of ‘d’ electrons =6)
In Cl = 1s² 2s² 2p⁶ 3s² 3p⁵
total p electrons =11 which are not equal to number of d electrons in Fe⁺²
p-electrons in Ne =1s² 2s² 2p⁶=6
s-electrons in Mg=1s² 2s² 2p⁶ 3s² =6.