The electronic configuration of Curium (Cm, Z = 96) is………

The correct answer is Option (1) → 5f⁷, 6d¹, 7s²

Curium is an actinoid. The actinoids follow radon (Z = 86), and their electrons enter the 5f, 6d and 7s orbitals. Their general configuration is [Rn]5f^1–146d^0–17s². The 7s orbital is always filled with 2 electrons, and a half-filled 5f⁷ or full 5f¹⁴ set is extra stable.

For Cm, the electrons beyond the radon core:

    \( \displaystyle 96-86=10\ \text{electrons} \)

Filling 7s² leaves 8 electrons. Seven go into 5f to make the stable half-filled 5f⁷ set, and the last one enters 6d:

    Cm (Z = 96): [Rn] 5f⁷ 6d¹ 7s²   (7 + 1 + 2 = 10)

So the configuration of curium is 5f⁷, 6d¹, 7s².

NCERT (2026-27 edition):
The Actinoids – …