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Structure of Atom ISC Class 11 MCQ & Practice Questions

Practice Structure of Atom MCQs for ISC Class 11 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Structure of Atom Revision Guide for ISC Class 11 Chemistry

Structure of Atom is part of ISC Class 11 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.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

1. The electron was discovered through experiments involving:

  • A. Alpha scattering
  • B. Photoelectric emission only
  • C. Cathode rays
  • D. Canal rays
Answer: C
Explanation: Cathode-ray experiments established the existence of negatively charged electrons.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

2. The charge-to-mass ratio of the electron was measured by:

  • A. Bohr
  • B. J. J. Thomson
  • C. Rutherford
  • D. Chadwick
Answer: B
Explanation: J. J. Thomson determined the e/m ratio of cathode-ray particles.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

3. The charge on an electron was accurately measured by:

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

ISC Class 11 Chemistry · Structure of Atom · Very Hard

4. The neutron was discovered by:

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

ISC Class 11 Chemistry · Structure of Atom · Very Hard

5. Rutherford's alpha-scattering experiment showed that most of an atom is:

  • A. Filled completely by electrons
  • B. A solid sphere
  • C. Empty space
  • D. Occupied by a uniform positive charge
Answer: C
Explanation: Most alpha particles passed through undeflected, indicating that atoms are largely empty space.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

6. Rutherford concluded that nearly all positive charge and mass are concentrated in the:

  • A. Entire atomic volume uniformly
  • B. Nucleus
  • C. Electron cloud
  • D. Outermost shell
Answer: B
Explanation: Large-angle scattering required a tiny, dense, positively charged nucleus.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

7. The main failure of Rutherford's atomic model was its inability to explain:

  • A. Atomic stability
  • B. Existence of nuclei
  • C. Positive charge of protons
  • D. Mass of electrons
Answer: A
Explanation: Classical electrodynamics predicted orbiting electrons should radiate energy and collapse into the nucleus.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

8. According to Planck's quantum theory, energy is emitted or absorbed in packets of magnitude:

  • A. h/ν
  • B. ν/h
  • C. hcν
  • D. hν
Answer: D
Explanation: The energy of one quantum is E = hν.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

9. The energy of a photon is directly proportional to its:

  • A. Mass
  • B. Amplitude only
  • C. Frequency
  • D. Wavelength
Answer: C
Explanation: E = hν, so photon energy increases with frequency.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

10. For electromagnetic radiation in vacuum, wavelength and frequency are related by:

  • A. c = hν
  • B. c = νλ
  • C. c = ν/λ
  • D. c = λ/ν
Answer: B
Explanation: The speed of light equals frequency multiplied by wavelength.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

11. As wavelength decreases, frequency:

  • A. Increases
  • B. Decreases
  • C. Remains constant
  • D. Becomes zero
Answer: A
Explanation: Because c = νλ is constant in vacuum, ν is inversely proportional to λ.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

12. The line spectrum of hydrogen supports the idea that electronic energies are:

  • A. Continuous
  • B. Always zero
  • C. Independent of quantum number
  • D. Quantised
Answer: D
Explanation: Discrete spectral lines arise from transitions between discrete energy levels.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

13. The Rydberg equation is used to calculate:

  • A. Nuclear radius only
  • B. Atomic density
  • C. Wavelengths or wavenumbers of hydrogen spectral lines
  • D. Electron mass
Answer: C
Explanation: The Rydberg relation describes spectral transitions in hydrogen-like species.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

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

  • A. Microwave region
  • B. Ultraviolet region
  • C. Visible region
  • D. Infrared region
Answer: B
Explanation: Transitions ending at n=1 produce ultraviolet radiation.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

15. The Balmer series of hydrogen lies mainly in the:

  • A. Visible region
  • B. Ultraviolet region
  • C. X-ray region
  • D. Radio region
Answer: A
Explanation: Transitions ending at n=2 include the visible hydrogen lines.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

16. The Paschen series corresponds to transitions ending at:

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

ISC Class 11 Chemistry · Structure of Atom · Very Hard

17. In the Bohr model, an electron in a permitted stationary orbit:

  • A. Has arbitrary angular momentum
  • B. Must fall into the nucleus
  • C. Does not continuously radiate energy
  • D. Continuously loses energy
Answer: C
Explanation: Bohr postulated non-radiating stationary states of definite energy.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

18. Bohr quantisation of angular momentum is expressed as:

  • A. mvr = 0
  • B. mvr = nh/2π
  • C. mvr = h/n
  • D. mvr = 2πnh
Answer: B
Explanation: Allowed orbital angular momenta are integral multiples of h/2π.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

19. For a hydrogen-like species, orbital radius varies approximately as:

  • A. n²/Z
  • B. Z/n²
  • C. n/Z²
  • D. 1/nZ
Answer: A
Explanation: Bohr radius for level n is proportional to n² divided by nuclear charge Z.

ISC Class 11 Chemistry · Structure of Atom · Very Hard

20. For hydrogen-like species, energy of the nth orbit varies as:

  • A. -n²/Z²
  • B. Z/n
  • C. -n/Z
  • D. -Z²/n²
Answer: D
Explanation: The bound-state energy is proportional to -Z²/n².

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Structure of Atom Practice Tests

Structure of Atom Frequently Asked Questions

How should I prepare Structure of Atom for ISC Class 11 Chemistry?

Revise the core concepts first, make a short list of important relationships or exceptions, and then solve chapter-focused MCQs while reviewing every error.

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What should I do after getting an MCQ wrong?

Identify whether the mistake came from a concept gap, calculation, unit, sign, wording or memory error, review that point, and then attempt a similar question again.

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