Question

The order of negative electron gain enthalpy of Li, Na, S, Cl is

• A. Na $>$ S $>$ Cl $>$ Li
• B. Cl $>$ S $>$ Li $>$ Na
• C. Cl $>$ Li $>$ S $>$ Na
• D. Li $>$ Na $>$ S $>$ Cl

Hint:

Halogens have the highest negative electron gain enthalpies.

Answer 1

The Correct Option is B

Chlorine has the highest negative electron gain enthalpy due to its high effective nuclear charge and smaller size, making it easier to accept an electron. Sulfur is next, followed by lithium and sodium. Alkali metals (Li and Na) have low negative electron gain enthalpies because adding an electron to their already stable s$^1$ configuration is relatively unfavorable. The correct order is Cl $>$ S $>$ Li $>$ Na.