As you move down a column (group) of the periodic table, how does the atomic radius change?

• A. It first increases, then decreases.
• B. It remains the same.
• C. It decreases.
• D. It increases.

Answer: (D)

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. Recall that as you move down a group (column) 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 generally causes the atomic radius to increase.
4. Consider the effect of shielding: inner electron shells reduce the effective nuclear charge felt by outer electrons, allowing them to spread out more and further increase atomic size.
5. Conclude that because of the addition of electron shells and increased shielding, the atomic radius increases as you move down a group in the periodic table.