Home/
Competitive Exams/
JEE Main & Advanced/
Chemistry/
Atomic Structure/
Question 600220
JEE Chemistry · Medium

Atomic Structure: Unpaired electrons MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

Timer-based practiceDetailed answer reviewMobile-friendly flow
Unpaired electronsMediumQuestion 600220

Question

The number of unpaired electrons in Fe²⁺ ([Ar] 3d⁶) is:
  1. A
    2
  2. B
    4
    Correct
  3. C
    5
  4. D
    6

Correct answer

4

Explanation

Fe²⁺: 3d⁶. Filling 5 d-orbitals: 5 electrons go in singly (Hund), 6th pairs with one. Unpaired = 4. Magnetic moment = √(n(n+2)) = √24 ≈ 4.9 BM.

Review Atomic Structure notesStart timed chapter practice