How does the atomic radius change as you move from top to bottom within a group in the periodic table?

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

Answer: (B)

Verified step by step guidance

1. Understand that the atomic radius refers to the average distance from the nucleus of an atom to the outermost electrons.
2. Recall 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. Recognize that adding more electron shells increases the distance between the nucleus and the outermost electrons, which tends to increase the atomic radius.
4. Consider the effect of shielding, where inner electron shells reduce the effective nuclear charge felt by outer electrons, allowing the outer electrons to be held less tightly and thus increasing the atomic radius.
5. Conclude that because of the addition of electron shells and increased shielding, the atomic radius increases as you move from top to bottom within a group in the periodic table.