As you move down a group in the periodic table, how does the atomic radius of the elements change?

• A. The atomic radius remains the same.
• 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 the atomic radius is the average distance from the nucleus to the outermost electrons in an atom.
2. Recognize that as you move down a group in the periodic table, each successive element has an additional electron shell (energy level) compared to the one above it.
3. Know that adding more electron shells increases the distance between the nucleus and the outermost electrons, which tends to increase the atomic radius.
4. Consider that although the nuclear charge (number of protons) increases down the group, the effect of increased electron shielding from inner shells reduces the effective nuclear attraction on the outermost electrons.
5. Conclude that due to the addition of electron shells and shielding effect, the atomic radius increases as you move down a group in the periodic table.