# What is the Lewis Dot Structure for BrO_2^- and what are the formal charges on each atom?

We have $7 + 6 + 6 + 1$ valence electrons to distribute, i.e. $\text{10 electron pairs.}$
$O = B r - {O}^{-}$.
Going from left to right, there are 2 lone pairs on the doubly bound oxygen, 2 lone pairs on Br, and 3 lone pairs on the singly bound oxygen (and since this centre owns 7 electrons, it has a formal negative charge). This distribution of electron pairs about $B r$, bonding and non-bonding, is tetrahedral to a first approx. and the $\angle O - B r - O$ bond angle should be 104-5""^@, compressed from the the ideal tetrahedral /_109.5""^@ by the influence on the non-bonding lone pairs.