How Many Valence Electrons Does The Element Bromine Have?

Counting the  4th shell orbitals and their electrons, Bromine has two 4s
electrons and five 4p electrons, giving it a total of 7 valence
electrons.

Br has the following electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁵, therefore Br has 7 electrons in the valence shell and has the capacity to accept 1 electron for bonding.

You can easily find out how many valance electrons an element carries by looking at the group number of the element on the periodic table.
As Bromine is in group 7, so it has 7 valence electrons.