MCQ Questions for Class 9 Science Chapter 4 Structure of the Atom

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.Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in the discovery of

(a) electron
(b) proton
(c) nucleus in the atom
(d) atomic mass

Answer: (b) atomic mass


Q2.Which of the following correctly represents the electronic distribution in the Mg atom?

(a) 3, 8, 1
(b) 2, 8, 2
(c) 1, 8, 3
(d) 8, 2, 2

Answer: (b) 2, 8, 2


Q3.The ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is 14. What is the number of electrons in the ion?

(a) 13
(b) 10
(c) 14
(d) 16

Answer: (b) 10


Q4.The first model of an atom was given by

(a) N. Bohr
(b) E. Goldstein
(c) Rutherford
(d) J.J. Thomson

Answer: (d) J.J. Thomson


Q5.Which of the following statement is always correct?

(a) An atom has equal number of electrons and protons.
(b) An atom has equal number of electrons and neutrons.
(c) An atom has equal number of protons and neutrons.
(d) An atom has equal number of electrons, protons and neutrons.

Answer: (a)


Q6.Which of the following isotope is used in the treatment of blood cancer?

(a) P-32
(b) I-131
(c) Co-60
(d) any of these

Answer: (a) P-32


Q7.An alpha particle is also known as:

(a) subatomic particle
(b) an unionised helium atom
(c) a neutral particle
(d) a doubly-charged helium ion

Answer: (d) a doubly-charged helium ion


Q8. What prevents an atom from being collapsed?

(a) The nuclear forces
(b) Movement of electrons in discrete energy levels
(c) The electron-electron repulsions
(d) All of these

Answer. (b) Movement of electrons in discrete energy levels


Q9. Which of the following pairs are isobars?

(a) 17Cl35 & 17Cl37
(b) 18Ar40 & 20Ca40
(c) 6C12 & 6C14
(d) None of these

Answer. (b) 18Ar40 & 20Ca40


Q10. Which radioactive element is used in the treatment of cancer?

(a) Iodine-131
(b) Uranium-234
(c) Plutonium-239
(d) Cobalt-60

Answer. (d) Cobalt-60


Q11. Which of the following is an incorrect statement in reference with observation in Rutherford’s α-particle scattering experiment?

(a) Some of the α-particles rebound after hitting the gold foil
(b) Some of the particles deflected from their path
(c) Some of the particles not pass through the gold foil
(d) Most of the particles pass straight through the gold foil

Answer. (a) Some of the α-particles rebound after hitting the gold foil



Q12. Which of the following is an incorrect statement in reference with observation in Rutherford’s α-particle scattering experiment?

(a) Some of the α-particles rebound after hitting the gold foil
(b) Some of the particles deflected from their path
(c) Some of the particles not pass through the gold foil
(d) Most of the particles pass straight through the gold foil

Answer. (a) Some of the α-particles rebound after hitting the gold foil


Q13. Which scientist gave the concept of fixed energy levels around the nucleus?

(a) Ernest Rutherford
(b) Neils Bohar
(c) J.J.Thomsan
(d) None of these

Answer. (b) Neils Bohar


Q14. Which of the two will be chemically more reactive, Sulphur(S) with atomic number 16 or Chlorine (Cl) with atomic number 17?

(a) Chlorine
(b) Sulphur
(c) Both are equally reactive
(d) Can’t say

Answer. (a) Chlorine


Q15.How many electrons are present in M-shell of an element with atomic number 20?


(a) 5
(b) 8
(c) 12
(d) 18

Answer: (b) 8


Q16. What property of an element determines its chemical behaviour?

(a) Size of an element
(b) Valency of an element
(c) Molar mass of the element
(d) None of these

Answer. (b) Valency of an element


Q17. What prevents an atom from being collapsed?

(a) The nuclear forces
(b) Movement of electrons in discrete energy levels
(c) The electron-electron repulsions
(d) All of these

Answer. (b) Movement of electrons in discrete energy levels


Q18.The charge on an electron is equal to:


(a) 1.6 × 10-19 C of -ve charge
(b) 2.6 × 10-19 C of -ve charge
(c) 1.6 × 10-22 C of -ve charge
(d) 1.6 × 10-23 C of -ve charge

Answer: (a) 1.6 × 10-19 C of -ve charge



Q19.An alpha particle is also known as:


(a) subatomic particle
(b) an unionised helium atom
(c) a neutral particle
(d) a doubly-charged helium ion

Answer: (d) a doubly-charged helium ion


Q20.Isobars do not differ in the number of


(a) protons
(b) electrons
(c) neutrons
(d) nucleons

Answer: (d) nucleons


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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