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Topic Atomic mass
Asked 3 times across 2 UPSC exams over 1 years (2020–2021), peaking in 2020.
Key insights
- Most tested in NDA — 2 of 3 PYQs
- Most asked in 2020
- Recurs across 2 years (2020–2021)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
NDA 2020 → CAPF 2020
How the concept evolved
Rising — more than half its appearances (3 of 3) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
NDA2021
Chlorine occurs in nature in two isotopic forms of masses 35 u and 37 u in the ratio of 3 : 1 respectively. What is the average atomic mass of the Chlorine atom ?
- A 36·1 u
- B 35·5 u ✓
- C 36·5 u
- D 35·1 u
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
CAPF2020
Which one of the following is the average atomic mass of chlorine atom?
- A 35.9 u
- B 35.5 u ✓
- C 35.0 u
- D 37.0 u
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
NDA2020
Atomic mass of an element is equal to the sum of number of
- A electrons and protons only
- B protons and neutrons only ✓
- C electrons and neutrons only
- D electrons, protons and neutrons
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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