Do you want to improve your understanding of general science questions, especially on the topics of Atomic Structure? Inspired by the NCERT GK book, this effort offers you a carefully selected set of general science (chemistry) GK questions with answers. These GK question and answer sets, which cover the fundamental concepts of atoms, molecules and atomic structure are ideal for students, competitive exam candidates, and inquisitive learners. These science-based tests, which feature an easy-to-understand format, help improve memory retention and solidify fundamentals. Our collection of science and chemistry questions will help you learn more effectively, whether you’re studying for school exams or general knowledge assessments.
In this blog post, we’ve compiled 50 Most Important General Science GK Questions on the Atom & Atomic Structure with detailed answers as a part of the Science GK effort by our team. These questions are ideal for aspirants preparing for UPSC, SSC, Railway, CDS, NDA, State PSC, and other government exams. Understanding these facts not only strengthens your static GK but also gives an edge in science, especially in the physical science and chemistry sections.
Multiple-Choice Question (Questions on Atoms & Atomic Structure)
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📘 Atoms and Molecules
- Who proposed the concept of indivisible particles of matter called Parmanu?
a) Democritus
b) Maharishi Kanad
c) Aristotle
d) Dalton - Which Greek philosopher introduced the term “atom”?
a) Democritus
b) Plato
c) Leucippus
d) Pythagoras - The Law of Conservation of Mass was given by:
a) Joseph Proust
b) Antoine Lavoisier
c) John Dalton
d) Rutherford - According to the Law of Constant Proportion, water always has hydrogen and oxygen in the mass ratio:
a) 2:1
b) 3:8
c) 1:8
d) 14:3 - Dalton’s atomic theory stated that atoms are:
a) Indivisible and indestructible
b) Divisible
c) Always visible
d) Variable in mass - Which postulate of Dalton’s theory explains the Law of Definite Proportion?
a) Atoms are indivisible
b) Atoms of same element are identical
c) Atoms combine in fixed whole number ratios
d) Atoms can be created - Atomic radius is measured in:
a) Metres
b) Microns
c) Nanometres
d) Angstrom - The SI unit of atomic mass is now written as:
a) amu
b) u (unified mass)
c) gram
d) kg - The standard reference for atomic mass is:
a) Oxygen-16
b) Carbon-12
c) Hydrogen
d) Nitrogen - Which element has an atomic mass of 23 u?
a) Magnesium
b) Sodium
c) Sulphur
d) Calcium - The smallest particle of an element that retains its chemical properties is:
a) Molecule
b) Compound
c) Atom
d) Proton - The smallest particle of a substance capable of independent existence is:
a) Atom
b) Ion
c) Molecule
d) Proton - The number of atoms in a molecule is called:
a) Mass number
b) Atomicity
c) Valency
d) Atomic number - Which element is diatomic?
a) Argon
b) Oxygen
c) Sulphur
d) Phosphorus - Atomicity of phosphorus is:
a) Monoatomic
b) Diatomic
c) Tetra-atomic
d) Polyatomic - The combining capacity of an element is called:
a) Atomicity
b) Atomic mass
c) Valency
d) Ionisation energy - A positively charged ion is called:
a) Cation
b) Anion
c) Proton
d) Molecule - Which of these is a polyatomic ion?
a) Na+
b) Cl–
c) SO₄²–
d) O²– - The formula of aluminium oxide is:
a) AlO
b) Al₂O₃
c) AlO₂
d) Al₃O₂ - The formula of calcium hydroxide is:
a) Ca(OH)₂
b) CaOH₂
c) CaH₂O
d) Ca₂OH - The molecular mass of water is:
a) 15 u
b) 18 u
c) 20 u
d) 17 u - Formula unit mass of NaCl is:
a) 46.5 u
b) 58.5 u
c) 23 u
d) 71 u - Molecular mass of HNO₃ is:
a) 45 u
b) 54 u
c) 63 u
d) 73 u - How many atoms are present in a molecule of H₂S?
a) 1
b) 2
c) 3
d) 4 - Which cluster of atoms acts as a single ion?
a) Monatomic ion
b) Polyatomic ion
c) Neutral atom
d) Nucleons
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📘 Atomic Structure
- Who discovered canal rays?
a) E. Goldstein
b) Rutherford
c) Bohr
d) J.J. Thomson - The particle with negligible mass and negative charge is:
a) Proton
b) Neutron
c) Electron
d) Positron - The charge on a proton is:
a) Zero
b) +1
c) –1
d) +2 - The charge on an electron is:
a) +1
b) –1
c) 0
d) +2 - Thomson’s model of atom is also called:
a) Watermelon model
b) Plum pudding model
c) Solar system model
d) Nuclear model - Rutherford’s experiment used:
a) Beta particles
b) Neutrons
c) Alpha particles
d) Protons - Rutherford discovered:
a) Electron
b) Proton
c) Nucleus
d) Neutron - Radius of nucleus is about how many times less than that of atom?
a) 10²
b) 10³
c) 10⁴
d) 10⁵ - Rutherford’s model failed because:
a) Atoms were indivisible
b) Electrons were stationary
c) Electrons should collapse into nucleus
d) Atoms had no nucleus - Bohr suggested that electrons revolve in:
a) Random paths
b) Discrete orbits
c) Elliptical paths
d) Unstable rings - Neutron was discovered by:
a) Rutherford
b) Bohr
c) Thomson
d) Chadwick - Which subatomic particle has no charge?
a) Proton
b) Electron
c) Neutron
d) Positron - The formula for maximum number of electrons in a shell is:
a) 2n
b) n²
c) 2n²
d) 2n³ - Maximum electrons in L shell are:
a) 2
b) 6
c) 8
d) 18 - Maximum electrons in M shell are:
a) 8
b) 12
c) 18
d) 32 - The electrons in the outermost shell are called:
a) Valence electrons
b) Protons
c) Neutrons
d) Nucleons - An atom with 8 protons and 8 electrons has charge:
a) Positive
b) Negative
c) Neutral
d) Cannot say - Atomic number of carbon is:
a) 5
b) 6
c) 7
d) 12 - Mass number is the sum of:
a) Protons and electrons
b) Protons and neutrons
c) Neutrons and electrons
d) All three particles - Atoms of same element with different mass numbers are:
a) Isotopes
b) Isobars
c) Isomers
d) None - Atoms of different elements with same mass number are:
a) Isotopes
b) Isobars
c) Isomers
d) None - Chlorine has isotopes of masses:
a) 35, 36
b) 35, 37
c) 36, 38
d) 34, 35 - The average atomic mass of chlorine is:
a) 35
b) 37
c) 35.5
d) 36 - An isotope of iodine is used in treatment of:
a) Cancer
b) Goitre
c) Malaria
d) Diabetes - An isotope of cobalt is used in treatment of:
a) Goitre
b) Tuberculosis
c) Cancer
d) Typhoid
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Answer Key
| S. No. | Answer | S. No. | Answer |
| 1 | B. Maharishi Kanad | 26 | A. E. Goldstein |
| 2 | A. Democritus | 27 | C. Electron |
| 3 | B. Antoine Lavoisier | 28 | B. +1 |
| 4 | C. 1:8 | 29 | B. –1 |
| 5 | A. Indivisible and indestructible | 30 | B. Plum pudding model |
| 6 | C. Atoms combine in fixed whole number ratios | 31 | C. Alpha particles |
| 7 | C. Nanometres | 32 | C. Nucleus |
| 8 | B. u (unified mass) | 33 | D. 10⁵ |
| 9 | B. Carbon-12 | 34 | C. Electrons should collapse into nucleus |
| 10 | B. Sodium | 35 | B. Discrete orbits |
| 11 | C. Atom | 36 | D. Chadwick |
| 12 | C. Molecule | 37 | C. Neutron |
| 13 | B. Atomicity | 38 | C. 2n² |
| 14 | B. Oxygen | 39 | C. 8 |
| 15 | C. Tetra-atomic | 40 | C. 18 |
| 16 | C. Valency | 41 | A. Valence electrons |
| 17 | A. Cation | 42 | C. Neutral |
| 18 | C. SO₄²– | 43 | B. 6 |
| 19 | B. Al₂O₃ | 44 | B. Protons and neutrons |
| 20 | A. Ca(OH)₂ | 45 | A. Isotopes |
| 21 | B. 18 u | 46 | B. Isobars |
| 22 | B. 58.5 u | 47 | B. 35, 37 |
| 23 | C. 63 u | 48 | C. 35.5 |
| 24 | C. 3 | 49 | B. Goitre |
| 25 | B. Polyatomic ion | 50 | C. Cancer |
Tips for Aspirants – Why These GK Questions Matter?
If you’re aiming for exams like UPSC, SSC, Railways, or other State Public Service Commissions, mastering General Science questions is a must. Because science GK questions consistes a significant part of it. Questions from “Atom & Atomic Stucture” are frequently repeated in exams because they establish a scientific foundation for understanding the topics of General science.
🟢 These GK questions with answers help in:
- Strengthening your static GK base
- Quick revision of conceptual theories
- Differentiating between similar-sounding options
Pro Tip: Revise these questions multiple times, focus on keywords, and try linking each theory to a scientist’s name—it really helps in the elimination strategy!
Conclusion
We hope you found this collection of 50 MCQs on the Atom & Atomic Stucture helpful in your exam preparation. General Science isn’t just about memorising formulae and terminologies—it’s about understanding how our discipline continues to evolve from the very beginning.
👉 Stay tuned for General Science GK Part-3
✍️ For more GK questions with answers, visit our dedicated 👉 GK Section.
