(a) In group 1 of alkali metals, the chemical reactivity increases down the group from lithium to francium.
(b) In group 17 of halogen elements, the chemical reactivity decreases down the group from fluorine to iodine.
(a) In group 1 of alkali metals, the chemical reactivity increases down the group from lithium to francium.
(b) In group 17 of halogen elements, the chemical reactivity decreases down the group from fluorine to iodine.