Chemistry

Question Analysis
This question evaluates the student's ability to apply the trend of atomic radius down a group and compare multiple elements.

Key Concept Explanation
Atomic radius generally increases as you move down a group due to the addition of new electron shells, which outweighs the increased nuclear charge.

Step-by-step Solution
1. Identify the elements: Cl, Br, I, and At, all in Group 17 (Halogens).
2. Compare their positions in the periodic table: Cl (Period 3), Br (Period 4), I (Period 5), and At (Period 6).
3. As you move down a group, the atomic radius increases.
4. ...