The hexaquo manganese $(II)$ ion contains five unpaired electrons,while the hexacyano manganese $(II)$ ion contains only one unpaired electron. Explain using Crystal Field Theory.

(N/A)

$[Mn(H_{2}O)_{6}]^{2+}$	$[Mn(CN)_{6}]^{4-}$
$Mn$ is in the $+2$ oxidation state.	$Mn$ is in the $+2$ oxidation state.
The electronic configuration is $d^{5}$.	The electronic configuration is $d^{5}$.

The crystal field is octahedral. Water $(H_{2}O)$ is a weak field ligand,while cyanide $(CN^-)$ is a strong field ligand.
In $[Mn(H_{2}O)_{6}]^{2+}$,the weak field ligand does not cause pairing of electrons,resulting in the configuration $t_{2g}^{3}e_{g}^{2}$,which has $5$ unpaired electrons.
In $[Mn(CN)_{6}]^{4-}$,the strong field ligand causes pairing of electrons,resulting in the configuration $t_{2g}^{5}e_{g}^{0}$,which has $1$ unpaired electron.