Calculate the formal charge and the oxiation state of Cr in chromate `(CrO_(4)^(2-))ion`.

Explanation

Structure of `CrO_(4)^(2-)` ion :
Formal charge on an atom = No of valence electrons in the atom
-NO of unshared electrons
`-1//2` No pof shared electrons
Formal charge on double bondeed oxygen atoms
`=6-4-1//2xx12=0=6-4-1//2xx4=0`
Formal charge onl single bonded oxygen atom `=6-6-1//2xx2=-1`
Total charge on chromate ion `=0+2xx0+2xx(-1)=-2`
Oxidation state of Cr by taking oxidation state of oxygens as -2 =x+4(-2)=-2 or x=+6