Question

What is the oxidation state of $Mn$ in the given compound $Mn{O}_4{}^{2-}$?
(Answer is the modulus of oxidation state)

Answer 1

Let the oxidation state of $Mn$ in $Mn{O}_4^{2-}$ be $x$.
$x+4(-2)=-2$
$x=+6$
Hence, the oxidation state of $Mn$ in $Mn{O}_4^{2-}$ is $+6$.