Gadolinium (Gd, ) is a highly tested exception in the f-block. What is its exact ground-state electr — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

To maintain the extra stability of an exactly half-filled $4f^7$ subshell, the next electron enters the $5d$ subshell, resulting in $[Xe] 4f^7 5d^1 6s^2$.