Question

Electronegativity of chlorine is less than oxygen because:

• A. Oxygen has larger size than chlorine
• B. Oxygen has smaller size and more effective nuclear charge
• C. Chlorine has higher nuclear charge
• D. Both have same electronegativity

Hint:

In general, electronegativity increases as atomic size decreases and nuclear charge increases. Oxygen is more electronegative than chlorine due to its smaller size and stronger nuclear charge.

Answer 1

The Correct Option is B

Understanding Electronegativity:
Electronegativity is the tendency of an atom to attract electrons in a chemical bond. It is influenced by atomic size and the effective nuclear charge (Z_eff).

In the periodic table:
  • Electronegativity increases across a period (left to right).
  • Electronegativity decreases down a group (top to bottom).

Oxygen vs Chlorine:
  - Oxygen is in Period 2, Group 16, while Chlorine is in Period 3, Group 17.
  - Oxygen has a smaller atomic radius compared to chlorine.
  - Due to this, oxygen's valence electrons are closer to the nucleus and experience a stronger effective nuclear charge.
  - Hence, oxygen pulls shared electrons more strongly than chlorine.

Correct Reason:
Oxygen has smaller size and a greater effective nuclear charge, making it more electronegative than chlorine.

Final Answer: Option 2: Oxygen has smaller size and more effective nuclear charge