MCQ Questions for Class 9 Science Chapter 4 Structure of the Atom
Solving the Structure of the Atom Multiple Choice Questions of Class 9 Science Chapter 4 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Structure of the Atom Class 9 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 4 Science Class 9 and cross-check your answers during preparation.
Multiple Choice Questions
Question 1.
In 1906, J.J. Thomson was awarded the Nobel prize for his discovery of:
(a) Electron
(b) Proton
(c) Neutron
(d) Positron
Answer
Answer: (a) Electron
Question 2.
Who discovered the nucleus of an atom?
(a) J.J. Thomson
(b) Neils Bohr
(c) Rutherford
(d) J. Chadwick
Answer
Answer: (c) Rutherford
Question 3.
Who is known as the ‘Father of nuclear Physics’?
(a) J. J. Thomson
(b) E. Rutherford
(c) Neils Bohr
(d) J. Chadwick
Answer
Answer: (b) E. Rutherford
Question 4.
An atomic number of an element equals to what present in the nucleus of its atom?
(a) Protons
(b) Electrons
(c) Both of them
(d) None of them
Answer
Answer: (a) Protons
Question 5.
Rutherford’s alpha-particle scattering experiment was responsible for the discovery of:
(a) Atomic nucleus
(b) Electron
(c) Proton
(d) Neutron
Answer
Answer: (a) Atomic nucleus
Question 6.
Isotopes of an element have:
(a) the same physical properties
(b) different chemical properties
(c) different number of neutrons
(d) different atomic numbers
Answer
Answer: (c) different number of neutrons
Question 7.
Number of valence electrons in CP ion are:
(a) 16
(b) 8
(c) 17
(d) 18
Answer
Answer: (b) 8
Question 8.
Which one of the following is a correct electronic configuration of sodium?
(a) 2, 8
(b) 8, 2, 1
(c) 2, 1, 8
(d) 2, 8, 1
Answer
Answer: (d) 2, 8, 1
Question 9.
Who used the term ‘ATOM’ for the first time?
(a) Rutherford
(b) John Dalton
(c) Chadwick
(d) Bohr
Answer
Answer: (b) John Dalton
Question 10.
Which of the following are called nucleon?
(a) Protons
(b) Neutrons
(c) Electrons
(d) Both, Protons and Neutrons
Answer
Answer: (d) Both, Protons and Neutrons
Question 11.
Which of the following particles was discovered first?
(a) Neutron
(b) Electron
(c) Proton
(d) Meson
Answer
Answer: (b) Electron
Question 12.
Which of the following atom does not have the neutron?
(a) Carbon
(b) Nitrogen
(c) Hydrogen
(d) Helium
Answer
Answer: (c) Hydrogen
Question 13.
Who gave the name ‘Proton’ the positively charged particles of an atom?
(a) Chadwick
(b) Goldstein
(c) Rutherford
(d) John Dalton
Answer
Answer: (c) Rutherford
Question 14.
The maximum number of electrons in any shell of an atom is:
(a) n2
(b) 2n2
(c) (n – 1)2
(d) 3n2
Answer
Answer: (b) 2n2
Question 15.
Which of the following rays have the maximum penetration power?
(a) α-rays
(b) X-rays
(c) γ-rays
(d) Cathod rays
Answer
Answer: (c) γ-rays
Question 16.
Who gave the first model of the atom?
(a) J.J. Thomson
(b) Chadwick
(c) Goldstein
(d) Neils Bohr
Answer
Answer: (a) J.J. Thomson
Fill in the Blanks.
Question 17.
______ are atoms of the same element, which have different mass numbers.
Answer
Answer: Isotopes
Question 18.
_______ are atoms having the same mass number but different atomic numbers.
Answer
Answer: Isobars
Question 19.
Neutrons are present in the nucleus of all atoms, except ________
Answer
Answer: hydrogen
Question 20.
α-particles are doubly-charged _________ ions.
Answer
Answer: helium
Question 21.
Neutron was discovered by _______
Answer
Answer: Chadwick
Question 22.
The neutral particle in the nucleus of an atom is ________
Answer
Answer: neutron
Question 23.
Atomic number of sodium is _________
Answer
Answer: 11
Question 24.
The mass of an electron is about _________ times, the mass of a hydrogen atom.
Answer
Answer: \(\frac{1}{2000}\)
True/False.
Question 25.
Sir J.J. Thomson discovered the anode rays.
Answer
Answer: False
Question 26.
According to Rutherford, the positive charge of an atom is concentrated in its center.
Answer
Answer: True
Question 27.
Elements are defined by the number of protons they possess.
Answer
Answer: True
Question 28.
Valency is the combining capacity of an atom.
Answer
Answer: True
Question 29.
α-particles have a mass of 2u.
Answer
Answer: False
Question 30.
The mass of electrons is considered to be negligible and its charge is plus one.
Answer
Answer: False
Question 31.
According to Thomson, an atom consists of a positively charged sphere and the electrons are embedded in it.
Answer
Answer: True
Question 32.
The negative and positive charges are equal in magnitude. So, the atom as a whole is electrically neutral.
Answer
Answer: True
Match the Column.
Question 33.
| A | B |
| 1. Discovery of Proton | (i) Deuterium |
| 2. Hydrogen | (ii) 4 |
| 3. Valency of Magnesium | (iii) Positive charge |
| 4. Valency of Carbon | (iv) He |
| 5. Symbol of Helium | (v) H |
| 6. Symbol of Hydrogen | (vi) 2 |
| 7. Electron | (vii) E. Goldstein |
| 8. Proton | (viii) Negative charge |
Answer
Answer:
| A | B |
| 1. Discovery of Proton | (vii) E. Goldstein |
| 2. Hydrogen | (i) Deuterium |
| 3. Valency of Magnesium | (vi) 2 |
| 4. Valency of Carbon | (ii) 4 |
| 5. Symbol of Helium | (iv) He |
| 6. Symbol of Hydrogen | (v) H |
| 7. Electron | (viii) Negative charge |
| 8. Proton | (iii) Positive charge |
Answer in Word/Sentence.
Question 34.
What is the value of charge on a proton?
Answer
Answer: 1.6 × 10-19 coulomb positive charge
Question 35.
What is the value of charge on an electron?
Answer
Answer: 1.6 × 10-19 coulomb negative charge
Question 36.
What is the value of charge on a neutron?
Answer
Answer: Zero (0) or no charge
Question 37.
According to Neils Bohr, electrons can revolve only in certain orbits. What name was given by him to these certain orbits?
Answer
Answer: Discrete orbits of electrons
Question 38.
According to Bohr-Burry rules, which formula is used to express the maximum number of electrons in an orbit of an atom?
Answer
Answer: 2n2
Question 39.
What is the maximum number of electrons in the outermost shell, according to Bohr-Burry?
Answer
Answer: 8
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