Learn

Saturday, 31 October

JEE Main · Chemistry · Some Basic Concepts of Chemistry

Average Atomic Mass from Isotopes

JEE Main asked Average Atomic Mass from Isotopes once in the 108 shifts Lumi analysed, on 6 Sep 2020, Shift 2. It belongs to Mole Concept, in Some Basic Concepts of Chemistry (Chemistry).

Updated 2026-10-24

Times asked
1
in 1 shift
Years
1 of 8
First asked
2020
the only year
Pattern
Gone quiet
asked once so far

Questions on this idea a shift, by year

2017–2026. Asked in 2020. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.050.10’170.08’200’210’220’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 0 in 24 shifts · 2022: 0 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 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
  • 20240 of 18
  • 20230 of 12
  • 20220 of 24
  • 20210 of 24
  • 20201 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Single correct is the usual form. Skill tested: calculation.

  • Isotope ratio from average atomic mass

Difficulty

Easy 1Medium 0Hard 0

The question was multiple choice.

Every question

The question

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

  1. 6 Sep 2020, Shift 2 · Q40The average molar mass of chlorine is 35.5 g mol−135.5\ \mathrm{g\,mol^{-1}}. The ratio of 35Cl^{35}\mathrm{Cl} to 37Cl^{37}\mathrm{Cl} in naturally…EasySingle correct

Shift: 6 Sep 2020, Shift 2.

Same topic

Other ideas in Mole Concept

Mole Concept has 18 ideas JEE Main has asked; 12 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas