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Saturday, 31 October

JEE Main · Chemistry · Classification of Elements and Periodicity in Properties

Counting Unpaired Electrons

JEE Main asked Counting Unpaired Electrons 2 times in 2 of the 108 shifts Lumi analysed, in 2021 and 2024. It belongs to Quantum Numbers, in Classification of Elements and Periodicity in Properties (Chemistry). The longest wait between two years asking it was 3 years.

Updated 2026-10-24

Times asked
2
in 2 shifts
Years
2 of 8
First asked
2021
last in 2024
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2021 and 2024. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.050.10’170’200.03’210’220’230.05’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 0 in 24 shifts · 2023: 0 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20241 of 18
  • 20230 of 12
  • 20220 of 24
  • 20211 of 24
  • 20200 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Numerical value is the usual form. Skill tested: application.

  • Order/ranking of unpaired electrons
  • Spin-only magnetic moment of ground state atom

Difficulty

Easy 2Medium 0Hard 0

1 of the 2 questions had a numerical answer.

Every question

All 2 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 6 Apr 2024, Shift 2 · Q69Arrange the following elements in the increasing order of number of unpaired electrons in it. (A) Sc (B) Cr (C) V (D) Ti (E) Mn Choose the…EasyOther
  2. 17 Mar 2021, Shift 2 · Q53In the ground state of atomic Fe(Z=26Z = 26), the spin-only magnetic moment is __________×10−1\times 10^{-1} BM. (Round off to the Nearest…EasyNumerical value

Shifts: 17 Mar 2021, Shift 2, 6 Apr 2024, Shift 2.

Same topic

Other ideas in Quantum Numbers

Quantum Numbers has 23 ideas JEE Main has asked; 9 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas