MCQs
1. The smallest particle proposed by Acharya Kanada was called:
A. Atomos
B. Electron
C. Parmanu
D. Proton
Answer: C
2. The Greek word “atomos” means:
A. Charged particle
B. Invisible particle
C. Indivisible
D. Nucleus
Answer: C
3. Dalton’s atomic theory proposed that atoms are:
A. Visible particles
B. Divisible particles
C. Fundamental building blocks of matter
D. Made of energy only
Answer: C
4. Cathode rays were discovered by:
A. Rutherford
B. Bohr
C. J. J. Thomson
D. Chadwick
Answer: C
5. Cathode rays are streams of:
A. Protons
B. Neutrons
C. Electrons
D. Alpha particles
Answer: C
6. Electrons carry:
A. Positive charge
B. Neutral charge
C. Negative charge
D. Double positive charge
Answer: C
7. Thomson’s atomic model is popularly called:
A. Nuclear model
B. Planetary model
C. Plum pudding model
D. Quantum model
Answer: C
8. In Thomson’s model, electrons were:
A. Revolving around nucleus
B. Embedded in positive sphere
C. Outside the atom
D. Present only in nucleus
Answer: B
9. Rutherford’s gold foil experiment used:
A. Beta particles
B. Neutrons
C. Alpha particles
D. Electrons
Answer: C
10. Most alpha particles passed through gold foil because:
A. Atoms are positively charged
B. Atoms are mostly empty space
C. Nucleus is large
D. Electrons are absent
Answer: B
11. Rutherford discovered the:
A. Electron
B. Proton only
C. Nucleus
D. Neutron
Answer: C
12. The positively charged central part of atom is:
A. Shell
B. Electron cloud
C. Nucleus
D. Orbit
Answer: C
13. Rutherford’s model is also called:
A. Plum pudding model
B. Planetary model
C. Wave model
D. Quantum model
Answer: B
14. Rutherford’s model failed to explain:
A. Presence of electrons
B. Stability of atom
C. Positive charge
D. Gold foil experiment
Answer: B
15. According to Bohr, electrons revolve in:
A. Random paths
B. Fixed energy levels
C. Nucleus
D. Straight lines
Answer: B
16. The shell nearest to nucleus is:
A. L-shell
B. M-shell
C. K-shell
D. N-shell
Answer: C
17. Maximum electrons in K-shell are:
A. 1
B. 2
C. 8
D. 18
Answer: B
18. Maximum electrons in L-shell are:
A. 2
B. 4
C. 8
D. 18
Answer: C
19. The particle discovered by James Chadwick was:
A. Electron
B. Proton
C. Neutron
D. Alpha particle
Answer: C
20. Neutrons are:
A. Positively charged
B. Negatively charged
C. Neutral particles
D. Double charged
Answer: C
21. Atomic number is equal to:
A. Number of neutrons
B. Number of protons
C. Number of shells
D. Mass number
Answer: B
22. Mass number is equal to:
A. Protons + Electrons
B. Neutrons only
C. Protons + Neutrons
D. Electrons + Neutrons
Answer: C
A=p^+ + n^0
23. The number of protons and electrons in a neutral atom are:
A. Different
B. Equal
C. Zero
D. Random
Answer: B
24. Electronic configuration of sodium (Atomic number 11) is:
A. 2, 8
B. 2, 8, 1
C. 2, 1, 8
D. 8, 2, 1
Answer: B
25. The outermost shell of an atom is called:
A. Inner shell
B. Orbit
C. Valence shell
D. Nucleus
Answer: C
26. Valency is:
A. Mass of atom
B. Combining capacity of atom
C. Number of neutrons
D. Number of shells
Answer: B
27. Oxygen has electronic configuration 2,6. Its valency is:
A. 1
B. 2
C. 6
D. 8
Answer: B
28. Atoms having same atomic number but different mass numbers are:
A. Isobars
B. Isotones
C. Isotopes
D. Ions
Answer: C
29. Carbon-12 and Carbon-14 are:
A. Isobars
B. Isotopes
C. Different elements
D. Ions
Answer: B
30. Atoms having same mass number but different atomic numbers are:
A. Isotopes
B. Isobars
C. Molecules
D. Ions
Answer: B
Assertion–Reason MCQs
31.
Assertion (A): Most alpha particles passed undeflected in Rutherford’s experiment.
Reason (R): Most of the atom is empty space.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
32.
Assertion (A): Electrons do not lose energy in Bohr’s fixed orbits.
Reason (R): Electrons move in stationary energy levels.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
33.
Assertion (A): Isotopes have similar chemical properties.
Reason (R): They have same electronic configuration.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
34.
Assertion (A): Atomic number determines identity of an element.
Reason (R): Atomic number equals number of protons.
A. Both A and R are true, and R explains A
B. Both A and R are true, but R does not explain A
C. A is true but R is false
D. A is false but R is true
Answer: A
Case-Based MCQs
Case Study 1
A student performed Rutherford’s gold foil experiment using alpha particles.
35. Most alpha particles passed through the foil because:
A. Nucleus is large
B. Atom is mostly empty space
C. Electrons attract alpha particles
D. Gold is soft metal
Answer: B
36. A few alpha particles were deflected sharply because:
A. They hit dense nucleus
B. Electrons repelled them
C. Gold foil melted
D. Alpha particles lost energy
Answer: A
37. Rutherford concluded that positive charge is:
A. Spread uniformly
B. Present in electrons
C. Concentrated in nucleus
D. Absent in atom
Answer: C
Case Study 2
An atom has atomic number 17 and mass number 35.
38. Number of protons is:
A. 17
B. 18
C. 35
D. 52
Answer: A
39. Number of neutrons is:
A. 17
B. 18
C. 35
D. 52
Answer: B
Competency-Based MCQs
40. Which model first introduced the nucleus?
A. Dalton’s model
B. Thomson’s model
C. Rutherford’s model
D. Bohr’s model
Answer: C
41. Why are noble gases chemically less reactive?
A. They have zero electrons
B. Their outermost shell is complete
C. They lack neutrons
D. Their nucleus is unstable
Answer: B
42. Electronic configuration of magnesium (Atomic number 12) is:
A. 2, 8, 2
B. 2, 6, 4
C. 2, 8, 1
D. 8, 2, 2
Answer: A
43. Which isotope is used in cancer treatment?
A. Carbon-14
B. Uranium-235
C. Cobalt-60
D. Hydrogen-1
Answer: C
44. Which isotope is used to determine age of fossils?
A. Carbon-14
B. Uranium-235
C. Iodine-131
D. Cobalt-60
Answer: A
45. An atom has 20 protons and 21 neutrons. Its mass number is:
A=20+21=41
A. 20
B. 21
C. 41
D. 61
Answer: C
46. The valency of sodium (2,8,1) is:
A. 0
B. 1
C. 7
D. 8
Answer: B
47. Which statement about isotopes is correct?
A. Same neutrons but different protons
B. Same atomic number but different mass numbers
C. Same mass numbers but different atomic numbers
D. Same valency but different elements
Answer: B
48. The maximum number of electrons in M-shell is:
A. 8
B. 18
C. 32
D. 2
Answer: B
49. Which subatomic particle has negligible mass compared to proton?
A. Neutron
B. Electron
C. Nucleus
D. Alpha particle
Answer: B
50. Which statement BEST explains atomic stability according to Bohr?
A. Electrons remain stationary in nucleus
B. Electrons move randomly around atom
C. Electrons revolve in fixed energy levels without losing energy
D. Electrons continuously lose energy
Answer: C
