Which group of elements would generally have the largest atomic radii?

Group 1A
Group 2A
Group 5A
Group 7A

Group 1a because atom size decreases going left to right

Group 1A

As the atomic number of elements in Period 3 (Atomic number 11-18) increases, the atomic radius decreases. The atom with the largest atomic radius is Na which is located in the group 1.
This is because, the effect of increasing proton number is greater than that of the increasing effective nuclear charge; therefore, there is a greater nuclear attraction. The valence electrons are held closer towards the nucleus of the atom. As a result, the atomic radius decreases.

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Explanation:

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