MCQ Questions for Class 9 Science Chapter 3 Atoms and Molecules

Find here the NCERT Book Multiple Choice Questions from Class 9 Science book with Answers Pdf free download as per CBSE new exam pattern. This may assist you to understand and check your knowledge about the chapters. Students also can take a free test of the Multiple Choice Questions of Class 9 Science. Each question has four options followed by the right answer. These MCQ Questions are selected supported by the newest exam pattern as announced by CBSE.


Q1.The chemical symbol for nitrogen gas is

(a) Ni
(b) N2
(c) N+
(d) N

Answer: (b) N2


Q2.The radius of a hydrogen atom is:

(a) 10-2
(b) 10-4
(c) 10-9
(d) 10-10

Answer: (d) 10-10


Q3.The most remarkable concept that Dalton’s atomic theory proposed was that of the:

(a) atomic weight
(b) atomic mass
(c) molar mass
(d) none of them

Answer: (b) atomic mass


Q4.The chemical symbol for sodium is

(a) So
(b) Sd
(c) NA
(d) Na

Answer: (d) Na


Q5.Compounds composed of metals and non-metals contain:

(a) non-charged species
(b) charged species
(c) both of them
(d) none of them

Answer: (b) charged species


Q6.Which of the following has maximum number of atoms?

(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CO4

Answer: (d) 18 g of CO4


Q7.The word “mole” was introduced around 1896 by:

(a) Wilhelm Ostwald
(b) John Dalton
(c) Avogadro
(d) Vergilious

Answer: (a) Wilhem Ostwald


Q8.3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms in the solution are

(a) 6.68 × 1023
(b) 6.09 × 1022
(c) 6.022 × 1023
(d) 6.022 × 102321

Answer: (a) 6.68 × 1023


Q9.Which of the following represents the correct relation between Avogadro’s number (No), number of particles (N) and moles (n)?

(a) n = N / No
(b) n = No / N
(c) n = N No
(d) all are correct

Answer: (a) n = N / No


Q10.Which of the following has a maximum number of atoms?

(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CH4

Answer: (d) 18 g of CH4


Q11.The relative molecular mass of Na2S2O3.5H2O is

(a) 250 amu
(b) 250 g
(c) 248 amu
(d) 248 g

Answer: (c) 248 amu


Q12. A change in the physical state can be brought about

(a) only when energy is given to the system
(b) only when energy is taken out from the system
(c) When energy is either given to, or taken out from the system
(d) Without any energy change

Answer:(b) only when energy is taken out from the system


Q13.Percentage of calcium in calcium carbonate is

(a) 40
(b) 30
(c) 48
(d) 36

Answer: (a) 40


Q14. Which of the following statements is not true about an atom?

(a) Atoms are not able to exist independently.
(b) Atoms are the basic units from which molecules and ions are
formed.
(c) Atoms are always neutral in nature.
(d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.

Answer. (d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.


Q15. 1 u or 1 amu means

(a) 1/12th mass of C-12 atoms
(b) Mass of C-12 atom
(c) Mass of O-16 atom
(d) Mass of Hydrogen molecule

Answer. (a) 1/12th mass of C-12 atoms


Q16.How many times an atom of sulphur is heavier than an atom of carbon?

(a) 32 times
(b) 12 times
(c) 8/3 times
(d) 12/32 times

Answer: (c) 8/3 timesAnswer: (c) 8/3 times


Q17. Which of the following statements is not true about an atom?

(a) Atoms are not able to exist independently.
(b) Atoms are the basic units from which molecules and ions are
formed.
(c) Atoms are always neutral in nature.
(d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.

Answer. (d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.


Q18. 1 u or 1 amu means

(a) 1/12th mass of C-12 atoms
(b) Mass of C-12 atom
(c) Mass of O-16 atom
(d) Mass of Hydrogen molecule

Answer. (a) 1/12th mass of C-12 atoms


Q19.Which of the following would weigh the highest?

(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O

Answer: (c) 2 moles of CaCO3


Q20.Which of the following contains a maximum number of molecules?

(a) 1g CO2
(b) 1g N2
(c) 1g H2
(d) 1g CH4

Answer: (c) 1g H2


Class 9 Science Chemistry MCQ

Chapter 1 Matter in Our Surroundings
Chapter 2: Is Matter Around Us Pure
Chapter 3: Atoms and Molecules
Chapter 4: Structure of the Atom

Class 9 Science Biology MCQ

Chapter 5: The Fundamental Unit of Life
Chapter 6: Tissues
Chapter 7: Diversity in Living Organisms
Chapter 13: Why do we Fall Ill
Chapter 14: Natural Resources
Chapter 15: Improvement in Food Resources

Class 9 Science Physics MCQ

Chapter 8: Motion
Chapter 9: Force and Laws of Motion
Chapter 10: Gravitation
Chapter 11: Work and Energy
Chapter 12: Sound

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