What happens to the reactivity of group 7 elements as you move down the group?

As you move down group 7 of the periodic table, which includes the halogens, the reactivity of these elements decreases. This trend can be understood by considering how the atomic structure changes from one element to the next in the group.

Halogens, such as fluorine and chlorine, are known for their reactivity, particularly their ability to gain electrons during chemical reactions to form negative ions. As you move down the group from fluorine to iodine, the atoms increase in size because additional electron shells are added. This greater atomic radius means that the outermost electrons are further away from the nucleus.

The increased distance between the nucleus and the outer electrons reduces the effective nuclear charge experienced by these electrons. Consequently, it becomes more difficult for these larger atoms to attract additional electrons needed for reactions. Therefore, while elements at the top of the group, such as fluorine, are very reactive due to their strong ability to attract electrons, the elements towards the bottom, such as iodine, are less reactive.

This trend reflects the general principle in chemistry that the reactivity of nonmetals tends to decrease as you move down a group, primarily due to the increasing difficulty in gaining electrons as atoms become larger and the influence of the nucleus diminishes on the outer