Atoms and Molecules Class 9 MCQs

Atoms and Molecules Class 9 MCQ: To effectively prepare for their upcoming exams, it’s crucial for CBSE Class 9 students to practice Multiple Choice Questions (MCQs) in Science, especially on Chapter 3: Atoms and Molecules. These MCQs cover important concepts and topics from the CBSE board curriculum. With correct answers provided, students can use these MCQs to understand and boost their exam performance. Also access our free NCERT Solutions Class 9 Science and CBSE Notes Class 9 for better understanding of this Chapter.

Class 9 Science MCQs – Chapter-wise

1. Matter in Our Surroundings
2. Is Matter Around Us Pure
3. Atoms and Molecules
4. Structure of Atom
5. The Fundamental Unit of Life

Atoms and Molecules Class 9 MCQ

Access free atoms and molecules class 9 MCQ with answers PDF. Practicing these MCQs will helps students prepare for Class 9 Annual exams. Class 9 Science Chapter 3 MCQs also prepare students for CTET and KVS exams. Our Class 9 Science MCQs are prepared according to the latest CBSE syllabus 2024-25 while ensuring an appropriate level of difficulty.

Don’t Miss:

• Lakhmir Singh Chemistry Class 9 Solutions Chapter 3
• NCERT Solutions Class 9 Science Chapter 4
• NCERT Examplar Solutions Class 9 Science Chapter 3

Class 9 Science Atoms and Molecules MCQs (Easy Level)

Here are eight very short and Easy Level multiple-choice questions (MCQs) along with their answers for CBSE Class 9 Science chapter “Atoms and Molecules”:

Q1. Which of the following is NOT a subatomic particle?
a) Neutron
b) Proton
c) Electron
d) Ion
Answer: d) Ion

Q2. What is the smallest particle of an element that retains its properties?
a) Atom
b) Molecule
c) Ion
d) Neutron
Answer: a) Atom

Q3. Who proposed the plum pudding model of an atom?
a) J.J. Thomson
b) Ernest Rutherford
c) Niels Bohr
d) James Chadwick
Answer: a) J.J. Thomson

• CBSE Worksheets for Class 9 Biology
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Q4. The atomic number of an element is determined by the number of:
a) Protons
b) Electrons
c) Neutrons
d) Nucleons
Answer: a) Protons

Q5. Which of the following is NOT a compound?
a) Water (H2O)
b) Oxygen (O2)
c) Carbon dioxide (CO2)
d) Hydrochloric acid (HCl)
Answer: b) Oxygen (O2)

Q6. The mass number of atom is equal to total number of:
a) Protons and neutrons
b) Protons and electrons
c) Neutrons and electrons
d) Electrons only
Answer: a) Protons and neutrons

Q7. Who proposed the planetary model of an atom?
a) J.J. Thomson
b) Ernest Rutherford
c) Niels Bohr
d) James Chadwick
Answer: c) Niels Bohr

Q8. Which of the following is NOT a chemical reaction?
a) Rusting of iron
b) Burning of magnesium
c) Dissolving sugar in water
d) Melting of ice
Answer: d) Melting of ice

Q9. Which scientist’s experiment led to the discovery of the nucleus of an atom?
a) J.J. Thomson
b) Ernest Rutherford
c) Niels Bohr
d) Dmitri Mendeleev
Answer: b) Ernest Rutherford

Atoms and Molecules Class 9 Science MCQ (Moderate Level)

Q1. Which of the following statements best describes an atom?
a) Atoms are the smallest particles of matter that can exist independently.
b) Atoms are composed of protons and electrons only.
c) Atoms cannot be broken down further by chemical means.
d) Atoms of different elements have the same mass number.
Answer: a) Atoms are the smallest particles of matter that can exist independently.

Q2. What is the significance of the atomic number of an element?
a) It represents the number of protons in the nucleus of an atom.
b) It indicates the number of electrons in the outermost shell of an atom.
c) It determines the mass of the atom.
d) It reflects the number of neutrons in the nucleus.
Answer: a) It represents the number of protons in the nucleus of an atom.

Q3. Which model of the atom states that electrons are distributed in various energy levels or shells?
a) Rutherford’s model
b) Bohr’s model
c) Dalton’s model
d) Thomson’s model
Answer: b) Bohr’s model

Q4. What is the term used to describe atoms of the same element having different numbers of neutrons?
a) Isotopes
b) Ions
c) Molecules
d) Compounds
Answer: a) Isotopes

Q5. Which subatomic particle has negligible mass?
a) Proton
b) Electron
c) Neutron
d) Nucleus
Answer: b) Electron

Q6. The mass of an atom is mainly attributed to the combined masses of its components.
a) Protons and neutrons
b) Protons and electrons
c) Neutrons and electrons
d) Protons, neutrons, and electrons
Answer: a) Protons and neutrons

Q7. What is the charge of an alpha particle?
a) Positive
b) Negative
c) Neutral
d) Variable
Answer: a) Positive

Q8. Which of the following represents a molecular formula?
a) H
b) O2
c) NaCl
d) Fe
Answer: b) O2

Also Check: NCERT Book Class 9 Science

Chapter 3 Chemistry Class 9 Atoms and Molecules MCQs (Difficult Level)

Here are 10 difficult level multiple choice questions (MCQs) on the topic of “Atoms and Molecules” for Class 9 Science Chapter 3

Q1. Which of the following particles has the least mass?
a) Proton
b) Neutron
c) Electron
d) Positron
Answer: c) Electron

Q2. The number of molecules present in one mole of any substance is
a) 6.022 × 10^23
b) 6.002 × 10^23
c) 6.022 × 10^22
d) 6.002 × 10^22
Answer: a) 6.022 × 10^23

Q3. What is the mass of one atom of carbon-12 in grams?
a) 12 g
b) 1 g
c) 1/12 g
d) 6 g
Answer: c) 1/12 g

Q4. The formula unit mass of a compound is:
a) Molecular mass × Avogadro’s number
b) Molecular mass × Molar mass
c) Molecular mass × 1/Avogadro’s number
d) Molar mass × 1/Avogadro’s number
Answer: d) Molar mass × 1/Avogadro’s number

Q5. The empirical formula of a compound is CH₂ and its molecular mass is 56. The molecular formula will be:
a) C₂H₄
b) C₄H₈
c) C₃H₆
d) C₅H₁₀
Answer: b) C₄H₈

Q6. Which of the following is NOT a diatomic molecule?
a) Oxygen (O₂)
b) Nitrogen (N₂)
c) Hydrogen (H₂)
d) Carbon dioxide (CO₂)
Answer: d) Carbon dioxide (CO₂)

Q7. The number of atoms present in 11.5 grams of sodium is approximately:
a) 6.022 × 10^23
b) 3.011 × 10^23
c) 1.806 × 10^24
d)3.706 × 10^24
Answer: c) 1.806 × 10^24

Q8. Which of the following contains the maximum number of molecules?
(a) 19 CO2
(b) 1 g N2
(c) 1 g H2
(d) 1 g CH4
Answer: (c) 1 g H2

Q9. A sample of NH3 molecule, irrespective of source, contains 82.35% Nitrogen and 17.65% of Hydrogen by mass. This data supports:
(a) Law of Conservation of Mass
(b) Law of Multiple Proportions
(c) Law of Definite Proportions
(d) Avogadro’s Law
Answer: (c) Law of Definite Proportions

Q10. An element X has a valency of 2, while another element Y has a valency of 4. What compound will form when these two elements combine?
(a) XY
(b) XY2
(c) X2Y
(d) XY4
Answer: (b) XY2

Q11. The molecular formula of potassium nitrate is ________.
(a) KNO3
(b) KNO
(c) KNO2
(d) KON
Answer: (a) KNO3

Q12. 3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms present are:
(a) 6.68 × 10^23
(b) 6.09 × 10^22
(c) 6.022 × 10^23
(d) 6.022 × 10^21
Answer: (a) 6.68 × 10^23

Q13. The number of atoms in one mole of a substance is:
a) 6.022 × 10^23
b) 3.011 × 10^23
c) 1.806 × 10^24
d)3.706 × 10^24
Answer: a) 6.022 × 10^23

Q14. The mass of one mole of a substance is equal to its:
a) Atomic mass
b) Molecular mass
c) Formula unit mass
d) Molar mass
Answer: d) Molar mass