# What is the oxidation number of iron in Fe_2O_3?

$+ 3$
So we know that oxygen has a oxidation number of $- 2$. Since we have 3 oxygens this would give a total of $- 6$.
We know that the charge should be stable $\left(= 0\right)$, so therefore iron must have a oxidation number of $+ 3$ since $2 \cdot 3 = 6$.