Consider the elements bromine and chlorine; which element has a larger ionic radius?

Both elements form ions with a 1− charge: chlorine becomes Cl⁻ and bromine becomes Br⁻. Bromide has an additional occupied electron shell compared with chloride, so its outer electrons are farther from the nucleus and Br⁻ has the larger ionic radius. The correct choice is bromine.

AI-written and checked against the verified answer.