Which of the following best explains why the electronegativity of Cl is less than that of F?

• A. Cl has a larger atomic radius than F, resulting in a weaker attraction between the nucleus and bonding electrons.
• B. Cl forms more stable compounds than F, making it more electronegative.
• C. Cl has more protons than F, which increases its electronegativity.
• D. Cl is in a higher period, so its valence electrons experience less shielding.

Answer: (A)

Verified step by step guidance

1. Understand that electronegativity is the tendency of an atom to attract bonding electrons toward itself in a chemical bond.
2. Recall that electronegativity generally increases across a period (left to right) in the periodic table because the number of protons increases, pulling electrons closer.
3. Recognize that fluorine (F) is in period 2 and chlorine (Cl) is in period 3, meaning Cl has more electron shells than F, resulting in a larger atomic radius.
4. Understand that a larger atomic radius means the valence electrons are farther from the nucleus and experience more shielding from inner electrons, reducing the effective nuclear attraction on bonding electrons.
5. Conclude that because Cl's valence electrons are less strongly attracted due to its larger size and increased shielding, its electronegativity is less than that of F.