If Bromine can displace iodine, it means that Bromine is more reactive than iodine. This is because Bromine has a higher atomic number than iodine, which means that it has more protons in its nucleus. This makes the nucleus of Bromine more positively charged, which attracts the electrons in its outer shell more strongly. This makes the electrons in Bromine's outer shell less likely to be shared with other atoms, which makes Bromine more reactive.