Chemistry - Coordination Chemistry Question with Solution | TestHub

The Ni²⁺ ion has a $3d^8$ electronic configuration. The provided options correctly represent its distribution under various crystal fields.

A) Free Ion: Follows Hund's rule, filling five orbitals with three pairs and two unpaired electrons.

B) Tetrahedral: Splitting into $e$ (lower) and $t_2$ (higher) levels; 8 electrons result in $e^4{t}_2^4$.

C) Octahedral: Splitting into $t_{2g}$ (lower) and $e_g$ (higher) levels; 8 electrons fill them as $t_{2g}^6{e}_g^2$.

D) Square Planar: Large splitting leads to a diamagnetic configuration where the four lowest energy orbitals are fully paired ($d_{xz}^2{d}_{yz}^2{d}_{z^2}^2{d}_{xy}^2$), leaving $d_{x^2-y^2}$ empty.

Since all diagrams accurately reflect these physical principles, the answer is A, B, C.D