Arrange N, O and S in order of decreasing electron affinity : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Compare the electron affinities: Nitrogen has a stable, half-filled 2p^3 configuration, which makes its electron affinity extremely low (almost zero). Step 2: Oxygen is smaller than Sulfur, which creates significant electron-electron repulsion in its compact 2p subshell when an electron is added, making its electron affinity lower than that of Sulfur. Step 3: Consequently, the decreasing order of electron affinity is S > O > N, which corresponds to option (a).