(a) How does the chemical reactivity of alkali metals vary on going down in group 1 of the periodic table?
(b) How does the chemical reactivity of the halogens vary on going down in group 17 of the periodic table?
(a) The chemical reactivity of alkali metals increases on going down in group 1 of the periodic table.
(b) The chemical reactivity of halogens(non-metals) decreases on going down in group 17 of the periodic table.