How do you calculate valency of bromide?

Answer 1

You have to use configuration of electrons (spdf). In this case it will only go up to d. if we use the short hand configuration then bromine is 3d10 4s2 4p5. remember d goes before everything.

Answer 2

The valency of bromide (Br-) is 1 as it is a halogen element which typically forms ions with a charge of -1. The valency of an element is determined by its ability to form chemical bonds and gain or lose electrons to achieve a stable electron configuration.