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Chemistry - Structure of Atom

Practise 45 WBJEE previous year questions on Structure of Atom, compiled from papers spanning 2009 to 2026. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty WBJEE tests.

Structure of Atom has been asked in 18 of the 18 years of WBJEE papers analysed (2009–2026), with 45 questions in all. 56% of them were easy, 40% moderate and 4% tough. Most of its questions came from 2011, with 5 questions that year. In the last three years (2024–2026) it had 6 questions across 3 papers, about 2 per paper.

The chapter's 6 topics are not weighted equally: Electronic configuration (10 questions, 22%), Dual Behaviour of Matter and Heisenberg Uncertainty Principle (9 questions, 20%), and Quantum mechanical model (8 questions, 18%) have been asked the most. Over the last five years the most frequent topics have been Quantum mechanical model (4), Dual Behaviour of Matter and Heisenberg Uncertainty Principle (3), and Bohr's model (3). Dual Behaviour of Matter and Heisenberg Uncertainty Principle has produced the most tough questions (2).

  1. 1The plot of radial probability density against for an electron in orbital of a many electron atom is given below: The value of is2026Quantum mechanical model
  2. 2The mass of an electron is kg. If its K.E. is J, its wavelength is (approximately)2026Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  3. 3In the above nuclear reaction ' X ' will be2025Atomic Mass and Atomic Size
  4. 4Identify the ion having electronic configuration.2024Electronic configuration
  5. 5Consider an electron moving in the first Bohr orbit of a ion with a velocity . If it is allowed to move in the third Bohr orbit with a veloc2024Bohr's model
  6. 6Which hydrogen like species will have the same radius as that of Bohr orbit of hydrogen atom?2024Bohr's model
  7. 7Two base balls (masses: \(m_1=100 {~g}\), and \(m_2=50 {~g}\) ) are thrown. Both of them move with uniform velocity, but the velocity of \(m2023Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  8. 8The calculated spin-only magnetic moment values in \( {BM}\) for \( [ {FeCl}_4 ]^{-}\)and \( [ {Fe}( {CN})_6 ]^{3-}\) are2023Quantum mechanical model
  9. 9An electron in the \(5 {~d}\) orbital can be represented by the following \( (n, 1, m_0 )\) values2023Quantum mechanical model
  10. 10Which one of the following is the correct set of four quantum numbers ?2022Quantum mechanical model
  11. 11The de-Broglie wavelength for electron (e), proton and ion are in the following order. (Speed of e, p and are the same)2022Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  12. 12In Bohr model of atom, radius of hydrogen atom in ground state is and radius of ion in ground state is . Which of the following is correct?2022Bohr's model
  13. 13For the reaction \(14 N+ {}^{17} O+p\), Mass equivalent of energy is absorbed. Mass on the reactant side is amu and proton mass . The atomic2021Atomic Mass and Atomic Size
  14. 14The atomic masses of helium and neon are and amu respectively. The value of the de Broglie wavelength of helium gas at is times the de Brogl2021Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  15. 15The maximum number of electrons in an atom in which the last electron filled has the quantum numbers and is2020Electronic configuration
  16. 16The radius of the first Bohr orbit of a hydrogen atom is . The velocity of the electron in the first Bohr orbit is2020Bohr's model
  17. 17The number of unpaired electrons in the uranium atom is:2020Electronic configuration
  18. 18The difference between orbital angular momentum of an electron in a 4 f orbital and another electron in a 4 s orbital is2020Quantum mechanical model
  19. 19Which one of the following electronic arrangements is absurd?2019Electronic configuration
  20. 20Which of these species will have non-zero magnetic moment?2019Quantum mechanical model
  21. 21Which of the following electronic configuration is not possible?2018Electronic configuration
  22. 22The number of unpaired electrons in Ni (atomic number ) are2018Electronic configuration
  23. 23If the given four electronic configurations. (i) (ii) (iii) (iv) are arranged in order of increasing energy, then the order will be2017Electronic configuration
  24. 24Which of the following sets of quantum numbers represents the electron of2017Electronic configuration
  25. 25Which one of the following corresponds to a photon of highest energy?2017Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  26. 26The energy required to break one mole of hydrogen-hydrogen bonds in is . What is the longest wavelength of light required to break a single 2016Hydrogen spectrum
  27. 27The time taken for an electron to complete one revolution in Bohr orbit of hydrogen atom is2016Bohr's model
  28. 28The atomic number of cerium is 58 . The correct electronic confipuration of ion is2015Electronic configuration
  29. 29The emission spectrum of hydrogen discovered first and the region of the electromagnetic spectrum in which it belongs, respectively are2014Hydrogen spectrum
  30. 30As per de-Broglie's formula a macroscopic particle of mass and moving at a velocity of will have a wavelength of2014Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  31. 31Identify the correct statement.2013Quantum mechanical model
  32. 32Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?2012Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  33. 33If the first ionization energy of atom is then the second ionization energy of He atom is2012Bohr's model
  34. 34The energy of an electron in first Bohr orbit of \( {H}\)-atom is \(-13.6 {eV}\). The possible energy value of electron in the excited state2011Hydrogen spectrum
  35. 35The representation of the ground state electronic configuration of He by box - diagram as \( \) is wrong because it violates2011Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  36. 36The electronic transitions from \( {n}=2\) to \( {n}=1\) will produce shortest wavelength in (where \( {n}=\) principal quantum state)2011Hydrogen spectrum
  37. 37A radioactive atom \( {X}_{ {Y}}\) emits two \( \) particles and one \( \) particle successively. The number of neutrons in the nucleus of t2011Atomic Mass and Atomic Size
  38. 38An element belongs to Group 15 and third period of the periodic table. Its electonic configuration will be2011Electronic configuration
  39. 39In Sommerfeld's modification of Bohr's theory, the trajectory of an electron in a hydrogen atom is2010Bohr's model
  40. 40If a species has 16 protons, 18 electrons and 16 neutrons, find the species and its charge2010Atomic Mass and Atomic Size
  41. 41Which of the following orbitals will have zero probability of finding the electron in the yz plane ?2010Quantum mechanical model
  42. 42Identify and in the following2010Atomic Mass and Atomic Size
  43. 431 mole of photon, each of frequency , would have approximately a total energy of:2009Dual Behaviour of Matter and Heisenberg Uncertainty Principle
  44. 44If it is assumed that decays only by emitting and particles, the possible product of the decay is :2009Atomic Mass and Atomic Size
  45. 45For the Paschen series the values of and in the expression are2009Hydrogen spectrum

Frequently Asked Questions

1.How many questions are available for Structure of Atom?

This chapter includes 45 questions compiled from WBJEE papers spanning 2009 to 2026.

2.Are these questions only from WBJEE, or from other exams too?

These are WBJEE questions specifically for the Structure of Atom chapter. Questions from other exams like JEE Main or NTA Abhyas (JEE Main) are organised separately under their respective exam sections.

3.Is Structure of Atom an important chapter for WBJEE Chemistry?

Structure of Atom has appeared in 18 of the 18 years of WBJEE papers covered here, with 45 questions across 18 papers - about 3 per paper it appears in.

4.What is the difficulty level of Structure of Atom questions in WBJEE?

Of the 45 questions analysed for this chapter, 56% are easy, 40% moderate and 4% tough. 2011 had the most, with 5 questions.

5.Which topics in Structure of Atom should I focus on?

These topics have carried the most weightage in Structure of Atom:

  • Electronic configuration - 10 questions (22%)
  • Dual Behaviour of Matter and Heisenberg Uncertainty Principle - 9 questions (20%)
  • Quantum mechanical model - 8 questions (18%)
  • Dual Behaviour of Matter and Heisenberg Uncertainty Principle has produced the most tough questions (2).
6.Is Structure of Atom's weightage in WBJEE going up or down?

Across all 18 papers analysed, Structure of Atom has averaged about 2.5 questions per paper. In the last three years (2024–2026), that average has fallen, at about 2.0 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.