In potassium ferrocyanide,there are $..........$ pairs of electrons in the $t_{2g}$ set of orbitals.

If $\Delta_0 < P$,the correct electronic configuration for a $d^4$ system is .....

The crystal field stabilization energy $(CFSE)$ of $[Fe(H_2O)_6]Cl_2$ and $K_2[NiCl_4]$,respectively,are

Match List-$I$ with List-$II$. Choose the correct answer from the options given below:
| List-$I$ (Complex ion) | List-$II$ (Electronic Configuration) |
| :--- | :--- |
| $A. [Cr(H_2O)_6]^{3+}$ | $I. t_{2g}^2 e_g^0$ |
| $B. [Fe(H_2O)_6]^{3+}$ | $II. t_{2g}^3 e_g^0$ |
| $C. [Ni(H_2O)_6]^{2+}$ | $III. t_{2g}^3 e_g^2$ |
| $D. [V(H_2O)_6]^{3+}$ | $IV. t_{2g}^6 e_g^2$ |

For an octahedral complex of $Co$ $(Z = 27)$,which of the following has the highest value of $\Delta_0$?

The energies of $d_{xy}$ and $d_{z^2}$-orbitals in octahedral and tetrahedral transition metal complexes are such that