the elements in alkali metal and halogen groups of the periodic table are the most reactive since they only need to gain or lose one electron to become stable by filling their valence orbital. what happens to reactivity, moving down the column of a group?

a) reactivity stays the same because they are in the same group.
b) reactivity increases because the valence level is further from the nucleus of the atom.
c) reactivity decreases because the increased number of protons and electrons provides more stability.
eliminate
d) reactivity stays the same because the number of electrons needed to fill the valence orbital remains the same.