The halogens in Group 7 of the periodic table exhibit clear trends in their reactivity and chemical properties.
Explain the trend in reactivity (oxidising ability) as you go down Group 7 from fluorine to iodine.
A student mixes chlorine water, Cl2(aq)\text{Cl}_2\text{(aq)}Cl2(aq), with a solution of potassium bromide, KBr(aq)\text{KBr(aq)}KBr(aq).