Question

The number of unpaired electrons in $\left[NiCl_{4}\right]^{2-}, Ni\left(CO\right)_{4}$ and $\left[Cu\left(NH_{3}\right)_{4}\right]^{2+}$ respectively are :

• A. $2, 2, 1$
• B. $2, 0, 1$
• C. $0, 2, 1$
• D. $2, 2, 0$

Answer 1

Answer: (B)

$2, 0, 1$

Answer 2

Configuration for metal $(M)$ in various complex.

$Ni ^{2+}$ has $2$ unpaired electrons

$Ni ^{0}$ has zero unpaired electrons with $s p^{3}$-hybridisation.

$Cu ^{2+}$ has one unpaired electron with $d s p^{2}$-hybridisation.
$\therefore (b)$ is the correct answer, i.e.
Number of unpaired electron $(2,0,1)$