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Structure of Atom JENPAS MCQ & Practice Questions

Practice Structure of Atom MCQs for JENPAS Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Structure of Atom Revision Guide for JENPAS Chemistry

Structure of Atom is part of JENPAS Chemistry preparation. A strong revision plan should combine concept review with exam-style questions so that definitions, relationships, calculations and exceptions are recalled accurately.

Use the sample MCQs on this page to check understanding, then attempt the related ChemNexa tests for broader practice. When an answer is wrong, review the explanation and return to the underlying concept before attempting another set.

Important Topics

  • Core definitions and principles
  • Important equations or relationships
  • Common applications and examples
  • Frequently confused concepts
  • Exam-style multiple-choice questions
  • Error review and targeted revision

Revision Tip

Create a one-page summary of trends, structures, reactions, exceptions and key terminology for Structure of Atom, then test recall with mixed MCQs.

What to practise in Structure of Atom

Concept Revision

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Exam-style MCQs

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Performance Practice

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Top 20 Structure of Atom MCQs with Answers

These public questions are selected from the exact Structure of Atom chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

JENPAS Chemistry · Structure of Atom · Very Very Hard

1. The charge-to-mass ratio of electron was determined by:

  • A. Chadwick
  • B. Bohr
  • C. J. J. Thomson
  • D. Rutherford
Answer: C
Explanation: J. J. Thomson measured the e/m ratio of the electron.

JENPAS Chemistry · Structure of Atom · Very Very Hard

2. The elementary charge was accurately measured by:

  • A. Planck
  • B. Millikan
  • C. Bohr
  • D. Moseley
Answer: B
Explanation: Millikan's oil-drop experiment determined the electronic charge.

JENPAS Chemistry · Structure of Atom · Very Very Hard

3. The neutron was discovered by:

  • A. James Chadwick
  • B. Rutherford
  • C. Goldstein
  • D. Thomson
Answer: A
Explanation: Chadwick discovered the neutron in 1932.

JENPAS Chemistry · Structure of Atom · Very Very Hard

4. Cathode rays consist of:

  • A. Protons
  • B. Neutrons
  • C. Photons
  • D. Electrons
Answer: D
Explanation: Cathode rays are streams of negatively charged electrons.

JENPAS Chemistry · Structure of Atom · Very Very Hard

5. Canal rays are streams of:

  • A. Neutrons
  • B. Gamma photons
  • C. Positive ions
  • D. Electrons
Answer: C
Explanation: Canal or anode rays consist of positive ions.

JENPAS Chemistry · Structure of Atom · Very Very Hard

6. Rutherford's alpha-scattering experiment established that:

  • A. Electrons have fixed energies without a nucleus
  • B. Most atomic mass and positive charge are concentrated in a tiny nucleus
  • C. Electrons are embedded in positive matter
  • D. Atoms are indivisible
Answer: B
Explanation: Large-angle scattering requires a small, dense, positively charged nucleus.

JENPAS Chemistry · Structure of Atom · Very Very Hard

7. Most alpha particles passed undeflected through gold foil because:

  • A. Most of the atom is empty space
  • B. The nucleus is negatively charged
  • C. Electrons are extremely massive
  • D. Gold contains no nuclei
Answer: A
Explanation: Rutherford's experiment showed that atomic volume is mostly empty space.

JENPAS Chemistry · Structure of Atom · Very Very Hard

8. A major failure of Rutherford's classical model was its inability to explain:

  • A. Existence of nucleus
  • B. Positive charge of nucleus
  • C. Scattering of alpha particles
  • D. Atomic stability
Answer: D
Explanation: Accelerating orbiting electrons should radiate energy and collapse into the nucleus classically.

JENPAS Chemistry · Structure of Atom · Very Very Hard

9. In Bohr's model, angular momentum of an electron is:

  • A. h/4π
  • B. 2πnh
  • C. nh/2π
  • D. nh
Answer: C
Explanation: Bohr quantised angular momentum as mvr = nh/2π.

JENPAS Chemistry · Structure of Atom · Very Very Hard

10. For a hydrogen-like species, Bohr radius of the nth orbit varies as:

  • A. Zn²
  • B. n²/Z
  • C. Z/n²
  • D. n/Z²
Answer: B
Explanation: r_n is proportional to n²/Z.

JENPAS Chemistry · Structure of Atom · Very Very Hard

11. The relation between wavelength and frequency is:

  • A. c = νλ
  • B. c = ν/λ
  • C. λ = cν
  • D. ν = cλ
Answer: A
Explanation: For electromagnetic radiation, speed equals frequency times wavelength.

JENPAS Chemistry · Structure of Atom · Very Very Hard

12. Energy of one photon is:

  • A. h/ν
  • B. ν/h
  • C. hcν
  • D. hν
Answer: D
Explanation: Planck's quantum relation is E=hν.

JENPAS Chemistry · Structure of Atom · Very Very Hard

13. As wavelength decreases, photon energy:

  • A. Remains constant
  • B. Becomes zero
  • C. Increases
  • D. Decreases
Answer: C
Explanation: E=hc/λ, so energy is inversely proportional to wavelength.

JENPAS Chemistry · Structure of Atom · Very Very Hard

14. The electromagnetic radiation with the shortest wavelength among these is:

  • A. Microwaves
  • B. X-rays
  • C. Visible light
  • D. Infrared
Answer: B
Explanation: X-rays have much shorter wavelengths than visible, IR, and microwaves.

JENPAS Chemistry · Structure of Atom · Very Very Hard

15. The wave number is defined as:

  • A. 1/λ
  • B. λ/c
  • C. cλ
  • D. νλ
Answer: A
Explanation: Wave number is the reciprocal of wavelength.

JENPAS Chemistry · Structure of Atom · Very Very Hard

16. The Lyman series of hydrogen lies mainly in the:

  • A. Visible region
  • B. Infrared region
  • C. Microwave region
  • D. Ultraviolet region
Answer: D
Explanation: Lyman transitions terminate at n=1 and occur in ultraviolet.

JENPAS Chemistry · Structure of Atom · Very Very Hard

17. The Balmer series corresponds to transitions ending at:

  • A. n=3
  • B. n=4
  • C. n=2
  • D. n=1
Answer: C
Explanation: Balmer-series transitions terminate at the second energy level.

JENPAS Chemistry · Structure of Atom · Very Very Hard

18. The Paschen series corresponds to transitions ending at:

  • A. n=4
  • B. n=3
  • C. n=1
  • D. n=2
Answer: B
Explanation: Paschen transitions terminate at n=3 and lie in infrared.

JENPAS Chemistry · Structure of Atom · Very Very Hard

19. The Rydberg equation for hydrogen spectral lines involves:

  • A. Difference of inverse squares of principal quantum numbers
  • B. Sum of principal quantum numbers
  • C. Difference of wavelengths directly
  • D. Product of orbital radii
Answer: A
Explanation: Wave number is R(1/n1² - 1/n2²).

JENPAS Chemistry · Structure of Atom · Very Very Hard

20. The maximum number of spectral lines possible when an electron initially at n=5 de-excites through all routes is:

  • A. 5
  • B. 4
  • C. 20
  • D. 10
Answer: D
Explanation: Maximum lines = n(n-1)/2 = 5×4/2 = 10.

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Structure of Atom Practice Tests

Structure of Atom Frequently Asked Questions

How should I prepare Structure of Atom for JENPAS Chemistry?

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