Atomic Structure
ID: #2035 | Difficulty: easy
AI Quick Answer:
The correct option for this defence exam question is (A) which is 10. Detailed proof and explanation are supplied below.
An isotope of an element has an atomic number of 6 and a mass number of 16. What is the number of neutrons in its nucleus?
Key Takeaways for NDA & CDS Candidates
- Ensure you recall the standard formulas for Atomic Structure during UPSC exam preparation.
- Eliminating obviously incorrect choices based on dimensional analysis or limits saves valuable seconds.
- Expert tip: Written defence mock tests should be practiced weekly with strict negative marking rules.
Correct Answer: (A)
10
Step-by-Step Explanation
The mass number (A) of an atom is the sum of the atomic number (Z, which represents protons) and the number of neutrons (N).
Formula: Mass Number (A) = Protons (Z) + Neutrons (N)
Therefore, Neutrons (N) = Mass Number (A) - Atomic Number (Z)
Given:
Z = 6
A = 16
N = 16 - 6 = 10 neutrons.
Formula: Mass Number (A) = Protons (Z) + Neutrons (N)
Therefore, Neutrons (N) = Mass Number (A) - Atomic Number (Z)
Given:
Z = 6
A = 16
N = 16 - 6 = 10 neutrons.
| Question Metadata Summary | |
|---|---|
| Exam Category | UPSC NDA / CDS / AFCAT / Agniveer |
| Subject Unit | NDA Chemistry Questions |
| Sub-topic / Module | Atomic Structure |
| Correct Option | Option (A) |
| Target Year | UPSC Defence Exams 2026 |