Give an explanation as to why Br is smaller than Br^–.

Br^– has more protons than Br which causes repulsion in the nucleus, this expands the nucleus hence making Br^– larger.

Br^– has fewer electrons than Br which provides more space around the ion,

Br^– has more electrons than Br and the additional electron increases the repulsion which causes the electron cloud to expand.

Br has more electrons than Br^– and the outer electrons are more attracted to the nucleus. This compresses the atom hence making it smaller.