$A$ metal ion $M^{n+}$ having $d^6$ valence electronic configuration combines with three bidentate ligands to form a complex. Assuming crystal field splitting $(\Delta_0) >$ pairing energy,the $d$-orbital electronic configuration would be

Crystal field stabilization energy $(CFSE)$ for the complex $[Co(CN)_6]^{3-}$ will be:

Homoleptic octahedral complexes of a metal ion $M^{3+}$ with three monodentate ligands $L_1, L_2$ and $L_3$ absorb wavelengths in the region of green,blue and red respectively. The increasing order of the ligand strength is:

Match the electronic configurations in List-$I$ with appropriate metal complex ions in List-$II$ and choose the correct option.
[Atomic Number: $Fe=26, Mn=25, Co=27$]

List-$I$	List-$II$
$P$. $t_{2g}^6 e_g^0$	$1$. $[Fe(H_2O)_6]^{2+}$
$Q$. $t_{2g}^3 e_g^2$	$2$. $[Mn(H_2O)_6]^{2+}$
$R$. $e^2 t_2^3$	$3$. $[Co(NH_3)_6]^{3+}$
$S$. $t_{2g}^4 e_g^2$	$4$. $[FeCl_4]^{-}$
	$5$. $[CoCl_4]^{2-}$

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

Arrange the following Cobalt complexes in the order of increasing Crystal Field Stabilization Energy $(CFSE)$ value.
Complexes: $[CoF_{6}]^{3-}, [Co(H_{2}O)_{6}]^{2+}, [Co(NH_{3})_{6}]^{3+}$ and $[Co(en)_{3}]^{3+}$
$A: [CoF_{6}]^{3-}, B: [Co(H_{2}O)_{6}]^{2+}, C: [Co(NH_{3})_{6}]^{3+}, D: [Co(en)_{3}]^{3+}$
Choose the correct option: