Oxidation Number (or State)*

Calculate the oxidation number of the metal in the following coordination entity:
${\mathrm{K}}_3\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$

Calculate the oxidation number of the metal in the following coordination entity:
${\left[{\mathrm{CoBr}}_2{\left(\mathrm{en}\right)}_2\right]}^{+}$

Calculate the oxidation number of the metal in the following coordination entity:
$\left[{\mathrm{CrCl}}_3{\left({\mathrm{NH}}_3\right)}_3\right]$

Calculate the oxidation number of the metal in the following coordination entity:
${\left[{\mathrm{PtCl}}_4\right]}^{2-}$

Specify the oxidation number of the metal in the following coordination entity:
 ${\left[\mathrm{C}\mathrm{o}\left({\mathrm{H}}_2\mathrm{O}\right)\left(\mathrm{C}\mathrm{N}\right){\left(\mathrm{e}\mathrm{n}\right)}_2\right]}^{2+}$
 

Find the oxidation number of $\mathrm{Ni}$ in ${\mathrm{K}}_4\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]$

Find the oxidation number of $\mathrm{Fe}$ in ${\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$.

Find the oxidation number of $\mathrm{Fe}$ in ${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$.

Find the oxidation number of $\mathrm{Co}$ in  ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$.