# What is the oxidation number of Br in the BrO_3^- ion?

$B {r}^{V +}$
The sum of the oxidation numbers equals the charge on the ion. Oxygen normally takes a $- I I$ oxidation number and it does so here. Thus $- 1 = - 2 \times 3 + B {r}^{O N}$.
So what are the oxidation numbers of $B r$ in $B r {O}_{4}^{-}$ and $K B r$ and $B r {O}^{-}$?