Chemistry

Question Analysis
This question evaluates the student's understanding of the periodic trend in electronegativity within a group and the reasoning behind this trend.

Key Concept Explanation
Electronegativity is the ability of an atom to attract shared electrons in a chemical bond. As you move down a group in the periodic table, the atomic radius increases, and the outer electrons are farther from the nucleus, reducing the effective nuclear charge on the valence electrons.

Step-by-step Solution
1. Identify the trend: Electronegativity decreases down a group.
2. Explain the reason: The atomic radius increases, and the outer electrons are farther from the nucleus, making it harder for the nucleus to attract additional electrons.
3. Conclude that the effect of increasing atomic radius outweighs the effect of increased nuclear charge.
4. Therefore, the correct answer...