# What is the electron configuration of a bromide ion?

For atomic $B r$, we have $Z = 35$, and thus for $B {r}^{-}$ we gots 36 electrons to distribute in the usual way......
$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 4 {s}^{2} 3 {d}^{10} 4 {p}^{6}$