Identify the correct increasing order of the magnitude of negative electron gain enthalpy for the following elements: O, S, F, and Cl.

Step-by-step solution

Halogens (Group 17) have a higher effective nuclear charge than chalcogens (Group 16) in the same period, resulting in a more negative electron gain enthalpy. Thus, F and Cl have higher magnitudes than O and S. Within Group 17, Cl has a more negative electron gain enthalpy than F. The small size of the F atom leads to high interelectronic repulsion in its compact 2p subshell, making the addition of an electron less favorable than in the larger 3p subshell of Cl. Similarly, within Group 16, S has a more negative ele