Question

Predict the number of unpaired electrons in the complex ion $[CoC{l}_4{]}^{2-}$, expected for the tetrahedral complex ion.

Answer 1

$C{o}^{2+}$ ion has $3d^7$ as outer electronic configuration.

In tetrahedral field it splits into $e_g^4{t}_{2g}^3$

Thus, it has 3 unpaired electrons.