NCERT Class 9 Science Chapter 4 Multiple Choice Question Answers
Structure of the Atom Class 9 MCQ Question Answers
Structure of the Atom Class 9 MCQ – Here is a compilation of Free MCQs of Class 9 Science Book Chapter 4 Structure of the Atom with Answers. Students can practice free MCQs as have been added by CBSE in the new Exam pattern. At the end of Multiple- Choice Questions, the answer key also has been provided for your reference.
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Q.1. Identify the incorrect statement.
(a) According to the alpha particle scattering experiment, very few alpha particles retrace their own path
(b) According to Niels Bohr’s atomic model, the energy of the second orbit is more than the energy of the first orbit.
(c) According to Thomson’s atomic model, electrons are embedded in uniform positive charge.
(d) According to Rutherford’s atomic model, electrons revolve around the nucleus in circular as well as elliptical paths
Q.2. A tripositive ion has 23 electrons and 30 neutrons. What is the atomic mass of the element?
(a) 56
(b) 53
(c) 50
(d) 55
Q.3. What would be the radius of the nucleus if 10-8 cm is the radius of the atom
(a) 10-8 cm
(b) 10-13 cm
(c) 10-5 cm
(d) 105 cm
Q.4. Identify the element(s) whose A-Z value is 14.
(i) Aluminium
(ii) Silicon
(iii) Phosphorus
(iv) Sulphur
(a) Only i
(b) i and ii
(c) i, ii and iv
(d) iii and iv
Q.5. Which of the following experiments led to the discovery of neutrons?
(a) Discharge tube experiment
(b) Alpha ray scattering experiment
(c) Chadwick’s experiment
(d) Oil drop experiment
Q.6. Match column A with column B.
| Column A | Column B |
| Atomic number | Valency |
| (A) 12 | (i) 3 |
| (B) 17 | (ii) 0 |
| (C) 10 | (iii) 2 |
| (D) 15 | (iv) 1 |
(a) A → ii, B → iv, C → iii, D → i
(b) A → iii, B → iv, C → ii, D → i
(c) A → iii, B → iv, C → i, D → ii
(d) A → iii, B → ii, C → i, D → iv
Q.7. Out of 1000 atoms of chlorine, 750 atoms have atomic mass 35u and 250 atoms have atomic mass 37u. What is the average atomic mass of chlorine atom?
(a) 35.5u
(b) 36u
(c) 36.5u
(d) 35.7u
Q.8. What is the total mass of neutrons present in Fe-56 atom? (Atomic number of iron is 26)
(a) 30 u
(b) 56 u
(c) 26 u
(d) 40 u
Q.9. Identify the decreasing order of specific charges of the particles: Electron(e), proton(p), neutron(n) and α particle.
(a) e, p, n, α
(b) p, e, n, α
(c) e, p, α, n
(d) n, α, p, e
Q.10. Which of the following set of elements ratio of atomic numbers is 1:2:3:4?
(a) H, He, Li, B
(b) He, Be, C, Ne
(c) Be, O, Mg, Ca
(d) B, Ne, P, Ca
Q.11. In the valence shell, which of the following pairs contains duplet and octet configuration respectively?
(a) Ne, Ar
(b) Ca+2 , O-2
(c) Li+1 , N-3
(d) Mg+2 , Be+2
Q.12. The maximum number of electrons that a valence shell of an atom can possess is _____
(a) 32
(b) 18
(c) 8
(d) 2
Q.13. Which of the following has a similar electronic configuration as that of argon?
(i) Potassium ion
(ii) Sulphide ion
(iii) oxide
(iv) chloride
(a) i and iii
(b) i, ii and iv
(c) ii and iv
(d) i, iii and
Q.14. The correct electronic configuration of potassium is _______?
(a) 2, 8, 4
(b) 2, 8, 8, 6
(c) 2, 8, 8, 18
(d) 2, 8, 8, 1
Q.15. Identify the correct statement(s);
(i) The penultimate shell of calcium is the M shell.
(ii) The charge of the stable ion with Z=16 is-2.
(iii) The valence shell of aluminium is N shell.
(iv) The maximum capacity of accommodating electrons of O shell is 50.
(a) i, ii, iv
(b) ii, iii, iv
(c) i, iii and iv
(d) i, ii, iii
Answer Key for Structure of the Atom Class 9 MCQs
| Q. | Ans | Q. | Ans |
| 1 | (d) | 9 | (c) |
| 2 | (a) | 10 | (d) |
| 3 | (b) | 11 | (c) |
| 4 | (b) | 12 | (c) |
| 5 | (c) | 13 | (b) |
| 6 | (b) | 14 | (d) |
| 7 | (a) | 15 | (a) |
| 8 | (a) |
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