Class 11 Chemistry Chapter 2 Structure of Atom MCQ

This set of Class 11 Chemistry Chapter 2 Multiple Choice Questions & Answers (MCQs) focuses on “Structure of Atom”. These MCQs are created based on the latest CBSE syllabus and the NCERT curriculum, offering valuable assistance for exam preparation.

1. What is the absolute charge of a proton?
a) +1.602176×10^-27
b) –1.602176×10^-19
c) +1.602176×10^-19
d) –1.602176×10^-27
View Answer

Answer: b
Explanation: According to the fundamental properties of particles, protons charge is +1.602176×10^-19C. It is a subatomic particle. Rutherford discovered protons. Its elementary charge is 1. Proton’s charge is positive.

2. Which of the following models are not the same as Thomson Model of Atom?
a) plum pudding model
b) watermelon model
c) raisin pudding model
d) nuclear model
View Answer

Answer: d
Explanation: Thomson proposed a model of the atom, in which electrons are embedded to make it as the stable electrostatic arrangement and such that positive charge is equally distributed around a sphere. Mass is assumed to be equally distributed. So. it has different names like plum pudding, watermelon and raisin pudding model.

3. Elements do emit radiation on their own and this property is known as _____
a) Radioactivity
b) Refraction
c) Absorption
d) Adsorption
View Answer

Answer: a
Explanation: Henri Becquerel discovered that elements emit radiation and termed this phenomenon as radioactivity. Later Curie on research found out about α-rays, β-rays and γ-rays. Later Rutherford concluded that α particles are helium nuclei.

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4. Which of the following statements you think is wrong regarding α particle scattering effect?
a) α particles mostly move through the gold foil having zero deflection
b) A small fraction are deflected
c) One in Twenty Thousand turns 180°
d) The thickness of the gold foil is about 100μm
View Answer

Answer: d
Explanation: In this effect, a thin foil (thickness 100nm) made up of gold and coated with fluorescent ZnS screen which is circular around it. α particles mostly move through the gold foil having zero deflection, a small fraction is deflected and one in twenty thousand turns 180°.

5. If the number of protons and neutrons of an element is 13 and 14 respectively, then what’s the atomic number(Z) and mass number(A)?
a) 13, 13
b) 13, 27
c) 14, 13
d) 27, 14
View Answer

Answer: b
Explanation: For an element, Atomic number(Z) = number of protons in that atoms = numbers of electrons in that atom; Mass number = number of protons + number of neutrons. So Z = 13 and A = 13 + 14 = 27. Hence that element is Aluminium.

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6. Which of the following is not an isotope of hydrogen?
a) protium
b) deuterium
c) tritium
d) helium
View Answer

Answer: d
Explanation: Protium has only 1 proton, deuterium has one proton and 1 neutron whereas tritium has one proton and two neutrons. They are represented by ₁H¹, ₁D² and ₁T³. Helium has 2 protons and two neutrons, hence can’t consider as an isotope. Isotope means having the same number of protons but differ in the number of neutrons.

7. Chemical properties of an atom are dependent on a number of electrons in that particular atom.
a) True
b) False
View Answer

Answer: a
Explanation: Yes, chemical properties of an atom is dependent on a number of electrons in that particular atom, which in turn is decided by the number of protons present in that atom. The number of neutrons has only a small effect on this.

8. Find out the number of neutrons, protons, and electrons of ₁₇Cl³⁷ respectively.
a) 20, 20, 17
b) 17, 17, 20
c) 20, 17, 17
d) 17, 17, 17
View Answer

Answer: c
Explanation: An atom is written in the symbol ZXA. By comparing it to ₁₇Cl³⁷, we get a number of protons as 17 and mass number as 37. Mass number – proton number = neutron number. Number of neutrons is 37 – 17 = 20. No. of protons = No. of electrons = 17.

9. Pick out the isobar of ₁₈Ar⁴⁰.
a) ₁₂Mg²⁴
b) ₂₆Fe⁵⁸
c) ₁₉K⁴⁰
d) ₂₈Ni⁶⁴
View Answer

Answer: c
Explanation: Isobar is a species of an element having the same mass number but a different atomic number. As per the above question, only ₁₉K⁴⁰ satisfies the conditions of ₁₈Ar⁴⁰ to be its isotope.

10. Gravitational force = Gm₁m₂/r².
a) True
b) False
View Answer

Answer: a
Explanation: The formula of gravitational force is given by Gm₁m₂/r². Here G is the gravitational constant, while m₁ and m₂ are the masses and r is the distance between m₁ and m₂. This theory is formulated when classic mechanics is applied to it.

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