Question

Among Li, Na, O, S, the elements having the most negative electron gain enthalpy and least negative electron gain enthalpy respectively are:

• A. O, Li
• B. O, Na
• C. S, Na
• D. S, Li

Hint:

Electron gain enthalpy trends: - Most negative for high electronegative, small atoms (O). - Least negative for alkali metals (Li, Na). Check periodic table trends.

Answer 1

The Correct Option is A

• Electron gain enthalpy: energy released when an atom gains an electron.
• More negative → releases more energy.
• Oxygen is more electronegative → most negative EGE.
• Lithium has least negative EGE among these (least tendency to gain electron).
• Hence correct option = O, Li.