Chemistry - PERIODIC TABLE Question with Solution | TestHub
Statement-1: The electron gain enthalpy of sulfur is more negative than that of oxygen.
Statement-2: Oxygen has a smaller atomic size than sulfur, leading to greater electron-electron repulsion when an additional electron is added to its compact 2p subshell.
Options:
Answer:
Solution:
Generally, electron gain enthalpy becomes more negative across a period and less negative down a group. However, the electron gain enthalpy of oxygen () is an exception, being less negative than that of sulfur (). Hence, Statement-1 is true.
Oxygen has a very small atomic size. When an electron is added to the compact 2p subshell of oxygen, it experiences significant interelectronic repulsion from the already present electrons. In contrast, sulfur has a larger atomic size, and the incoming electron enters the 3p subshell, where it experiences less repulsion, leading to a more negative electron gain enthalpy. Hence, Statement-2 is true and correctly explains Statement-1.
