Chemistry

Question Analysis
This question assesses the student's understanding of the trend in atomic radius down a group and the factors influencing this trend.

Key Concept Explanation
The atomic radius is affected by the number of electron shells and the nuclear charge. As you move down a group, new electron shells are added, which increases the distance between the nucleus and the outermost electrons. The increased electron shielding provided by these additional shells outweighs the effect of the increased nuclear charge.

Step-by-step Solution
1. Identify the trend: Atomic radius increases as you move down a group.
2. Understand the reason: Addition of new electron shells (higher principal quantum number n) increases the distance between the nucleus and the outermost electrons.
3. Note that the increased electron shielding provided by these additional s...