Questions on the Atomic Nucleus
20 Multiple-Choice Questions on the Atomic Nucleus
1. What is found in the nucleus of an atom?
A) Only electrons
B) Only protons
C) Protons and electrons
D) Protons and neutrons
E) Electrons and neutrons
2. What is the charge of the atomic nucleus?
A) Positive
B) Negative
C) Neutral
D) Varies by element
E) Depends on the number of neutrons
3. What is the mass number of an atom?
A) The number of protons
B) The number of electrons
C) The sum of protons and neutrons
D) The difference between protons and electrons
E) The number of neutrons only
4. Which particles in the nucleus are electrically neutral?
A) Electrons
B) Protons
C) Neutrons
D) Ions
E) Quarks
5. What force holds protons and neutrons together in the nucleus?
A) Electromagnetic force
B) Gravitational force
C) Weak nuclear force
D) Strong nuclear force
E) Magnetic force
6. Who discovered the nucleus?
A) Niels Bohr
B) J.J. Thomson
C) James Chadwick
D) Ernest Rutherford
E) Albert Einstein
7. What is the approximate diameter of an atomic nucleus?
A) 10⁻¹⁰ meters
B) 10⁻⁸ meters
C) 10⁻¹⁴ meters
D) 10⁻⁶ meters
E) 10⁻¹² meters
8. What property of the nucleus determines the identity of an element?
A) Number of neutrons
B) Number of electrons
C) Number of protons
D) Total mass
E) Atomic volume
9. What happens to the nucleus in radioactive decay?
A) It becomes negatively charged
B) It emits particles or radiation
C) It absorbs electrons
D) It disappears
E) It creates molecules
10. What is an isotope?
A) An atom with no electrons
B) An atom with extra protons
C) An atom with different numbers of neutrons
D) An atom with no nucleus
E) An atom with the same mass number as another element
11. The atomic number equals:
A) The total number of particles in the nucleus
B) The number of electrons
C) The number of neutrons
D) The number of protons
E) The sum of protons and neutrons
12. Which subatomic particles contribute most to atomic mass?
A) Electrons
B) Protons and neutrons
C) Only protons
D) Only neutrons
E) Ions
13. What part of the atom occupies most of its volume?
A) The nucleus
B) The electrons
C) The protons
D) The neutrons
E) The quarks
14. How is the nucleus affected in nuclear fission?
A) It loses all protons
B) It gains electrons
C) It splits into smaller nuclei
D) It emits photons
E) It combines with other atoms
15. What is nuclear fusion?
A) Splitting of heavy nuclei
B) Emission of alpha particles
C) Combining of light nuclei
D) Absorption of electrons
E) Formation of molecules
16. What is the neutron’s charge?
A) Positive
B) Negative
C) Neutral
D) Doubly negative
E) Depends on the atom
17. Why don’t protons in the nucleus repel each other?
A) Because of gravitational attraction
B) Because they’re neutralized by electrons
C) Because the strong nuclear force overcomes repulsion
D) Because of magnetic shielding
E) Because of weak nuclear force
18. The stability of a nucleus largely depends on:
A) Number of electrons
B) Number of protons only
C) Ratio of protons to neutrons
D) Temperature
E) Number of quarks
19. What particle is emitted during alpha decay?
A) One proton
B) One neutron
C) One electron
D) Helium nucleus
E) Hydrogen atom
20. What type of particle is emitted in beta-minus decay?
A) Proton
B) Neutron
C) Electron
D) Positron
E) Alpha particle
- Questions on Dalton’s Atomic Theory
- Questions on Atomic Structure
- Questions on Protons, Electrons, and Neutrons
Answer Key with Extended Explanations
1. D – The nucleus contains protons and neutrons.
2. A – The nucleus is positively charged, due to protons.
3. C – Mass number is the sum of protons and neutrons.
4. C – Neutrons have no electrical charge.
5. D – The strong nuclear force binds protons and neutrons together.
6. D – Ernest Rutherford discovered the nucleus in 1909.
7. C – The nucleus is about 10⁻¹⁴ meters in diameter.
8. C – The number of protons defines the element (atomic number).
9. B – In radioactive decay, the nucleus emits particles or energy.
10. C – Isotopes have same protons, different neutrons.
11. D – Atomic number = number of protons.
12. B – Protons and neutrons contribute nearly all the mass.
13. B – Electrons, though light, occupy most atomic volume.
14. C – In nuclear fission, the nucleus splits.
15. C – Nuclear fusion combines light nuclei, e.g., hydrogen into helium.
16. C – A neutron is electrically neutral.
17. C – The strong nuclear force keeps protons bound despite repulsion.
18. C – Nuclear stability depends on the proton-neutron ratio.
19. D – Alpha decay emits a helium nucleus (2 protons + 2 neutrons).
20. C – Beta-minus decay emits an electron from the nucleus.
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