Chemistry · Chapter 2 of 11

Structure of Atom: BPSC & UPPCS Prelims PYQs

11 previous-year questions on Structure of Atom. Each one opens to its answer and explanation.

1. 1. UPPSC Prelims 2025 Asked again

   With reference to 'Isotopes', which of the following statements is/are correct?
   1. Atoms with identical atomic numbers but different atomic mass numbers are known as isotopes.
   2. Protium, Deuterium and Tritium are isotopes of carbon.
   Select the correct answer from the code given below:

   1. AOnly 1
   2. BBoth 1 and 2
   3. CNeither 1 nor 2
   4. DOnly 2
   Answer and explanation →

2. 2. 70th BPSC Prelims 2024 Asked again

   Dalton's atomic theory successfully explained:
   i. Law of conservation of mass
   ii. Law of constant composition
   iii. Law of radioactivity
   iv. Law of multiple proportion

   1. Aii, iii and iv
   2. Bi, ii and iii
   3. Ci, ii and iv
   4. Di, iii and iv
   Answer and explanation →

3. 3. 70th BPSC Prelims 2024

   Who was the first one to propose a model for the structure of an atom?

   1. AE. Goldstein
   2. BRutherford
   3. CNiels Bohr
   4. DJ. J. Thomson
   Answer and explanation →

4. 4. 67th BPSC Prelims 2022

   The nucleus of an atom consists of

   1. Aelectrons and protons
   2. Bprotons and neutrons
   3. Celectrons only
   4. Delectrons and neutrons
   5. ENone of the above/More than one of the above
   Answer and explanation →

5. 5. 67th BPSC Prelims 2022

   Which among the following is an incorrect option?

   1. AAtom is electrically neutral due to the presence of protons and electrons inside the nucleus.
   2. BElectrons are negatively charged and have negligible mass.
   3. CAtomic number is the number of protons in an atom of an element.
   4. DIsotopes are useful as nuclear fuel, in medical field, in carbon dating, etc.
   5. ENone of the above/More than one of the above
   Answer and explanation →

6. 6. 67th BPSC Prelims 2022

   The mass number of a nucleus is

   1. Athe sum of the numbers of neutrons and protons
   2. Bthe total mass of neutrons and protons
   3. Calways more than the atomic weight
   4. Dalways less than its atomic number
   5. ENone of the above/More than one of the above
   Answer and explanation →

7. 7. 67th BPSC Prelims 2022 Asked again

   Isotopes of an element differ in

   1. Athe number of protons
   2. Bthe mass number
   3. Cthe number of electrons
   4. Dthe atomic number
   5. ENone of the above/More than one of the above
   Answer and explanation →

8. 8. 66th BPSC Prelims 2020

   The number of neutrons in the nucleus of plutonium nuclide (94Pu242) is

   1. A94
   2. B148
   3. C242
   4. D336
   5. ENone of the above / More than one of the above
   Answer and explanation →

9. 9. 65th BPSC Prelims 2019

   The number of electrons and neutrons in an element is 18 and 20 respectively. Its mass number is -

   1. A22
   2. B2
   3. C38
   4. D20
   5. ENone of the above / More than one of the above
   Answer and explanation →

10. 10. 45th BPSC Prelims 2001

    Which of the following is the electronic configuration of a metallic element?

    1. A2, 8
    2. B2, 8, 7
    3. C2, 8, 8
    4. D2, 8, 8, 2
    Answer and explanation →

11. 11. 45th BPSC Prelims 2001

    What is the mass number of an element, the atom of which contains two protons, two neutrons and two electrons?

    1. A2
    2. B4
    3. C6
    4. D8
    Answer and explanation →