$[FeF_6]^{3-}$ has $Fe$ atom . . . . . . hybridised with unpaired . . . . . . electrons.

Consider the transition metal ions $Mn^{3+}$, $Cr^{3+}$, $Fe^{3+}$, and $Co^{3+}$. All form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective $d$-orbitals of the complexes is:

Briefly explain the Valence Bond Theory $(VBT)$.

Match the coordination number and type of hybridisation with the distribution of hybrid orbitals in space based on Valence Bond Theory.

Coordination number and type of hybridisation	Distribution of hybrid orbitals in space
$a. 4, sp^3$	$i. \text{trigonal bipyramidal}$
$b. 4, dsp^2$	$ii. \text{octahedral}$
$c. 5, sp^3d$	$iii. \text{tetrahedral}$
$d. 6, d^2sp^3$	$iv. \text{square planar}$

Select the correct option.

The shape of $MnO_4^-$ ion and the hybridisation of $Mn$ in $MnO_4^-$ is

On the basis of valence bond theory,discuss the geometrical shapes and magnetic properties of the following $4$-coordinated complexes:
$(i)$ $[NiCl_{4}]^{2-}$
$(ii)$ $[Ni(CN)_{4}]^{2-}$
$(iii)$ $[Ni(CO)_{4}]$
$(iv)$ $MnO_{4}^{-}$