An element shows a lower first ionization energy than its predecessor in the same period. Which element exhibits this exception due to electron-electron repulsion?
Q1. An element shows a lower first ionization energy than its predecessor in the same period. Which element exhibits this exception due to electron-electron repulsion?
Answer: Oxygen
Explanation: Oxygen's half-filled p-orbital in O⁻ reduces stability, making removal easier. Nitrogen's half-filled p-orbital (option C) is unusually stable.