The halogens in Group 7 of the periodic table exhibit clear trends in their reactivity and properties.
Explain the trend in reactivity as you go down Group 7 from fluorine to iodine.
A student mixes bromine water, Br2(aq)\text{Br}_2\text{(aq)}Br2(aq), with a solution of sodium iodide, NaI(aq)\text{NaI(aq)}NaI(aq).