Question

The ratio of unpaired electrons present in d orbitals of $C{o}^{2+}$ and $C{r}^{3+}$Co2+ is ____.

• A. 2:1
• B. 1:3
• C. 3:1
• D. 4:3

Answer 1

Answer: (B)

1:3

Ground state configuration of cobalt

$=\left[Ar\right]3d^{7}4s^2$

Ground state configuration of ${Co}^{2+}$

Remove $2$ electrons

So only one unpaired $e^{-}$

Ground configuration of $Cr=4s^{1}3d^5{Cr}^{3+}=4s^{1}3d^2$

unpaired electrons $=3$

${Co}^{2+}:{Cr}^{3+}=1:3$