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CBSE Class 9 Science Important MCQs from Chapter 4 Structure of The Atom for Annual Exam 2020

Check MCQs on Class 9 Science Chapter 4 - Structure of the Atom to practice for the Annual Exam 2020.

Jan 13, 2020 15:44 IST
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CBSE 2020
CBSE 2020

Multiple Choice Questions (MCQs) on CBSE Class 9 Science Chapter- Structure of the Atom are provided here with answers. These questions are quite useful to prepare the objective type questions that will appear in the Class 9 Science Question Paper in the Annual Examination 2020.

Check below the important MCQs on Structure of The Atom:

1. Who discovered the electron?

(a) Rutherford

(b) Chadwick

(c) Thomson

(d) Goldstein

Answer. (c) Thomson

2. Which isotope is used in the nuclear power plants to generate electricity?

(a) Uranium 235

(b) Iodine 131

(c) Cobalt 60

(d) Uranium 238

Answer. (a) Uranium 235

3. Why was the Thomson’s Model of an atom failed?

i. It could not explain the screening of negative charges from that of positive

ii. It did not tell about the presence of electrons

iii. It did not give an idea about the discrete energy levels

iv. It explained the atom as a whole to be electrically neutral

Choose the correct option from the following:

(a) Only (iii)

(b) Both (i) & (iii)

(c) Only (i)

(d) Both (ii) & (iv)

Answer. (b) Both (i) & (iii)

4. What was the source of alpha particles in Rutherford scattering experiment?

(a) Hydrogen nucleus

(b) Argon nucleus

(c) Helium nucleus

(d) None of these

Answer. (c) Helium nucleus

5. 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

6. Which of the following does not match the characteristics of an Isotope?

(a) Isotopes of some elements are radioactive

(b) Isotopes are the atoms of different elements

(c) Isotopes differ in number of neutrons

(d) Isotopes have similar chemical properties

Answer. (b) Isotopes are the atoms of different elements

7. 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

8. Which of the following elements does not exhibit the electrovalencey?

(a) Sodium

(b) Calcium

(c) Carbon

(d) Chlorine

Answer. (c) Carbon

9. Which of the following statements is incorrect about the structure of an atom?

i. The whole mass of an atom is concentrated in the nucleus

ii. The atom is an indivisible particle

iii. The atom as a whole is neutral

iv. All the atoms are stable in their basic state

Choose the right option among the following:

(a) (i) and (iii)

(b) only  (ii)

(c) (ii) and (iv)

(d) none of these

Answer. (c) (ii) and (iv)

10. 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

 11. 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

12. Which of the following pairs are isobars?

(a) 17Cl35 & 17Cl37

(b)  18Ar40 & 20Ca40

(c)  6C12 & 6C14

(d) None of these

Answer. (b)  18Ar40 & 20Ca40

13. 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 

14. 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

15. Why do most of the elements try to participate in the chemical combinations?

i. To gain more electrons

ii. To achieve Inert Gas configuration

iii. To complete their octet

iv. To complete their inner shells

Choose the correct option among the following

(a) Both (i) & (iii)

(b) Both (ii) & (iii)

(c) Only (ii)

(d) Both (i) & (iv)

Answer. (b) Both (ii) & (iii)

You may also check the MCQs on other chapters from the links provided below:

Important MCQs on Class 9 Science Chapter - 1

Important MCQs on Class 9 Science Chapter - 2 

Important MCQs on Class 9 Science Chapter - 3

Links of other chapters will be provided very soon.

Also Check: 

CBSE Class 9 MCQs for Maths, Science, Social Science & English Exam 2020

CBSE Class 9 Science Important Questions & Answers for Annual Exam 2020

CBSE Class 9 Maths Important Questions & Answers for Annual Exam 2020

Class 9 Science NCERT Book and Solutions PDF

Class 9 Maths NCERT Book and Solutions PDF

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