Trying to find the right answer to this..

The p-Block Elements

Question

Arrange the following in order of decreasing property indicated:
(a) M—F, M—Cl, M—Brand M— l. (Ionic character)
(b) F₂,Cl₂,Br₂,I₂. (reactivity)

Answer

(a) M—F > M—Cl > M—Br > M—I.

(b) F₂ > Cl₂ > Br₂ > I₂.
because, as we move down the group: The atoms get larger. The outer shell gets further from the nucleus. The attraction between the nucleus and electrons gets weaker, so an electron is less easily gained.