[Urgent] 有關 Group I Metals

yes. the reducing power of metal is increasing down the group.
group I and group II have this trend.
it is because the reactivity of metal is increasing down the group.
activity of potassium is greater than that of sodium.
activity of calcium is greater than that of magnesium.
the atomic size is increasing down the group.
the outermost electron is easier to be lost to other atom.