The total oxide ion charge in a formula unit of mno is 2–. what is the charge on each manganese ion?

It is given that MnO2 has a formula charge of – 2. We know that each oxygen or oxide ion has also a charge of – 2, therefore there are a total of – 4 oxide charges. So we can write:

X + (- 4) = - 2

Where X is the charge of one manganese ion, so calculating for X:

X = - 2 + 4

X = 2

So the charge of manganese is 2+