How does the atomic radius change as you move from the top to the bottom of a chemical family (group) in the periodic table?

• A. The atomic radius remains constant.
• B. The atomic radius decreases.
• C. The atomic radius increases.
• D. The atomic radius first increases, then decreases.

Answer: (C)

Verified step by step guidance

1. Understand that a chemical family (group) in the periodic table consists of elements arranged vertically, sharing similar chemical properties.
2. Recall that atomic radius is the average distance from the nucleus to the outermost electrons in an atom.
3. As you move from the top to the bottom of a group, each successive element has an additional electron shell (energy level), which increases the size of the electron cloud.
4. Although the nuclear charge (number of protons) increases down the group, the effect of added electron shells causes increased electron shielding, reducing the effective nuclear attraction on the outermost electrons.
5. Therefore, the atomic radius increases as you move down a group because the outer electrons are farther from the nucleus and less tightly held.