Apotassium atom (atomic number 19) and a bromine atom (atomic number 35) can form a chemical bond through a transfer of one electron. the potassium ion that forms has 18 electrons. what best describes the bromide ion that forms? it is a negative ion that has one less valence electron than a neutral bromine atom. it is a positive ion that has one less valence electron than a neutral bromine atom. it is a negative ion that has one more valence electron than a neutral bromine atom. it is a positive ion that has one more valence electron than a neutral bromine atom.