Explain why the reactivity of elements in group 1 increases down the group but decrease in group 7 down the group

1,why does the reactivity of elements in group 1 (hydrogen,lithium,sodium,pottasium)increase as you continue down?

2, why does the reactivity of elements in group 7(florine,chorine) decrease as you continue down the group?

Atoms get bigger so electrons are not held as tightly and are lost more easily. So reactivity increases. Not sure if I would put H in group 1. Metals react by losing electrons so larger atoms lose electrons more readily as the outer electrons are further from nucleus and less attracted.

In group 7 atoms get bigger down the group. However, Group 7 react by gaining electrons. Attractive force of nucleus is greater with smaller atoms (protons closer to the outer shell and there is less shielding effect of inner shell. F is more reactive than Cl etc

group 1

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