Why does atomic radius generally increase as you move down a group on the periodic table?

• A. Because atoms lose electrons as you move down a group, making them larger.
• B. Because the effective nuclear charge increases significantly, pulling electrons closer to the nucleus.
• C. Because additional electron shells are added, increasing the distance between the nucleus and the outermost electrons.
• D. Because the number of protons decreases, causing the atom to expand.

Answer: (C)

Verified step by step guidance

1. Understand that atomic radius refers to the size of an atom, typically measured from the nucleus to the outer boundary of the electron cloud.
2. Recognize that as you move down a group in the periodic table, each successive element has an additional electron shell compared to the one above it.
3. Know that adding more electron shells increases the distance between the nucleus and the outermost electrons, which naturally increases the atomic radius.
4. Consider that although the number of protons (nuclear charge) also increases down a group, the effect of increased electron shielding from inner shells reduces the effective nuclear charge felt by the outer electrons.
5. Conclude that the increased shielding and added shells outweigh the increased nuclear charge, resulting in a larger atomic radius as you move down a group.