Question

Which of the following has maximum number or unpaired electrons?

• A. $C{u}^{+}$
• B. $Zn$
• C. $F{e}^{2+}$
• D. $N{i}^{3+}$

Answer 1

Answer: (C)

(i) $C{u}^{+}(Z=29)[Ar]3d^{10}4s^0$
It has no unpaired electron.
(ii) $Zn(Z=30)[Ar]3d^{10}4s^2$
It has no unpaired electron.
(iii) $F{e}^{2+}(Z=26)[Ar]3d^{6}4s^0$
It has four unpaired electrons.
(iv) $N{i}^{3+}(Z=28):[Ar]3d^{7}4s^0$
It has three unpaired electrons
Therefore $F{e}^{2+}$ has maximum number of unpaired electrons
A paramagnetic species has unpaired electrons. A diamagnetic species has no unpaired electrons.