Question

What is the oxidation state of each element in so32â?

Answer 1

 Same answer, different setup. We know that the sum of the oxidation numbers is zero for a compound and the ionic charge for a polyatomic ion, and we know that sulfite ion is -2. 

Create an algebraic equation by multiplying the subscripts times the oxidation number of a single element. 

+x -6 = -2 
+x -2 
S O3 

Solve for x 
x = +4