Predict the number of unpaired electrons in ${\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_6\right]}^{4-}$

Give the oxidation state, $\mathrm{d}-$orbital occupation and coordination of the central metal atom in the following complex:

${\mathrm{K}}_3\left[\mathrm{Co}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]$

Give the oxidation state, $\mathrm{d}$ orbital occupation and coordination number of the central metal ion in the following complex:

$\mathrm{cis}‐\left[\mathrm{Cr}{\left(\mathrm{en}\right)}_2{\mathrm{Cl}}_2\right]\mathrm{Cl}$

Give the oxidation state, $\mathrm{d}$ orbital occupation and coordination number of the central metal ion in the following complex:

${\left({\mathrm{NH}}_4\right)}_2\left[{\mathrm{CoF}}_4\right]$

Give the oxidation state, $\mathrm{d}$ orbital occupation and coordination number of the central metal ion in the following complex

$\left[\mathrm{Mn}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]{\mathrm{SO}}_4$