Question

how does the reactivity of the metal vary in a group

Answer 1

Increases down a group

Answer 2

Explanation:

Reactivity of metals depends on the tendency to lose electrons. If the atomic size increases, the valence electrons are easily removed thereby forming positive ion. In case of metals the atomic size increases as we move down the table. Reactivity of non-metals depends on the tendency to gain electrons. As we move down the group, the tendency to gain electrons decreases because as the atomic size increases, the effective nuclear charge decreases.