What is the oxidation number of manganese in the permanganate ion (mno4 - ) ?

a. 3

b. 2

c. 7

d. 2-

Each oxygen will have the oxidation number (2-), and we know the total charge is 1-. We have four oxygen atoms per molecule, so we can set up the equation:

(charge on Mn) + 4 (charge on O) = - 1

(charge on Mn) + 4 (-2) = - 1

(charge on Mn) - 8 = - 1

Charge on Mn = 7

The answer is C. 7