Chemistry Class 9 Chapter 2
Updated: 03 Sep 2023
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Chemistry Class 9 Chapter 2 is about the “Structure of an Atom.” This article includes topics such as Rutherford’s Atomic Model, Neil Bohr’s Atomic Theory, Fundamental Particles of an atom like Electrons, Protons and Neutron, Electronic Configuration and Isotopes.
Chemistry Class 9 Chapter 2 Notes
Chemistry 9th Class Chapter 2
Structure of an Atom
Chemistry Class 9 Chapter 2-MCQs
Dalton Atomic Theory
1. A Greek philosopher “Democritus” suggested that all———— can be further divided into tiny particles.(a) matter
(b) substances
(c) elements
(d) All of them
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All of them
2. The name of atom was given from the Greek word ————- which means indivisible.
(a) atomos
(b) atomics
(c) Halogens
(d) None of these
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atoms
3. The word atom was first used —————.
(a) 400AD
(b) 400 BC
(c) 600AD
(d) 600BC
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400 BC
4. No further work on atom was done until the ————– century.
(a) 18th
(b) 20th
(c) 19th
(d) 21st
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19th
5. John Dalton, after a lot of experiments, concluded that all matter must be composed of tiny particles called —-.
(a) Atom
(b) Element
(c) isotope
(d) None of these
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Atom
6. John Dalton states that an atom is ——————-.
(a) Invincible
(b) Indivisible
(c) Invisible
(d) None of these
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Indivisible
7. John Dalton presented his own theory about atom in —————–.
(a) 1806
(b) 1906
(c) 1808
(d) 1908
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1808
8. ————–is composed of very small particles called atoms.
(a) Matter
(b) Energy
(c) Numbers
(d) All of these
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Matter
9. Atom can neither be created nor ———————.
(a) Formulated
(b) Destroyed
(c) combined
(d) None of these
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Destroyed
10. Atoms combine with each other in ————– number ratio.
(a) Integers
(b) Quadratic
(c) Whole
(d) None of these
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Whole
11. Atoms of particular element are ———— in size shape, mass and also in other properties.
(a) Different
(b) Identical
(c) Atomic
(d) None of these
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Identical
12. All chemical reactions occur due to the combination or ————— of atoms.
(a) Separation
(b) Distillation
(c) Filtration
(d) None
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Separation
Rutherford’s Atomic Model
Rutherford’s Experiment
Main Points of Rutherford’s Atomic Model
Drawbacks of Rutherford’s Atomic Model
13. In———-, Rutherford performed an experiment to know the arrangement of electron and protons in an atom.(a) 1910
(b) 1912
(c) 1911
(d) 1913
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1911
14. In Rutherford experiment which part of the atom has been discovered?
(a) Energy levels
(b) Nucleus
(c) Other
(d) None
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Nucleus
15. ————— performed an experiment to determine the internal structure of the atom in 1911.
(a) J.J Thompson
(b) Max plank
(c) Rutherford
(d) None of these
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Rutherford
16. In Rutherford experiment, what he has used?
(a) Gold foil
(b) Gold bar
(c) Silver foil
(d) Tin plates
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Gold foil
17. He bombarded the ________ particles on gold foil from a radioactive source.
(a) Beta
(b) Alpha
(c) Gamma
(d) None of these
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Alpha
18. What radioactive source does Rutherford used?
(a) Polonium
(b) Thorium
(c) Radon
(d) None of these
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Polonium
19. This experiment showed that most of the volume occupied by the atom is —————.
(a) Bulky
(b) Small
(c) Empty
(d) None of these
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Empty
20. From this experiment, Rutherford concluded that an atom contains a ———– portion i.e. nucleus.
(a) Negative
(b) Positive
(c) Neutral
(d) None of these
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Positive
21. Similar charges ————–each other.
(a) Repel
(b) Attract
(c) Articulate
(d) All of these
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Repel
22. On the basis of his conclusion drawn from the experiment, Rutherford proposed a new model at atom called ————-model.
(a) Planetary
(b) Universal
(c) Room & Cat
(d) None of these
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Planetary
23. Atom consists of positively charged nucleus which contains ———and neutrons.
(a) Electrons
(b) Protons
(c) Fundamental particles
(d) None of these
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Protons
24. Electrons are ————around the nucleus just like the planets around the sun.
(a) Stand still
(b) Gathered
(c) Revolving
(d) None of these
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Revolving
25. The electrons around the nucleus would require ————- force.
(a) Centripetal
(b) Centrifugal
(c) Net
(d) Average
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Centripetal
26. The size of the ————- is very small as compared to the size of atom.
(a) proton
(b) Neutron
(c) Nucleus
(d) All of them
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All of them
27. Atom is ———— because electrons and protons will cancel the effect of each other.
(a) Negatively charge
(b) Neutral
(c) Positively charged
(d) None of these
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Neutral
28. Rutherford atomic model of an atom resembles our ________ system.
(a) Solar
(b) Universal
(c) Gravitational
(d) None of these
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Solar
29. Rutherford model is applicable to neutral bodies and not on ————.
(a) Isotopes
(b) Energy
(c) Charged bodies
(d) None of these
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Charged bodies
30. According to which scientist, electrons are charged bodies revolving around the nucleus and emit energy.
(a) Rutherford
(b) Schrodinger
(c) Maxwell
(d) None of these
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Maxwell
31. If electrons radiate energy continuously then the ———–spectrum will be obtained.
(a) Line
(b) Continuous
(c) Both
(d) None of these
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Continuous
32. Rutherford atomic model does not provide any explanation about ———— properties of elements.
(a) Chemical
(b) Physical
(c) Elemental
(d) None of these
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Chemical
Neil Bohr’s Atomic Theory
33. In ————-, Neil Bohr proposed a new atomic theory to overcome the defects of Rutherford atomic model.(a) 1901
(b) 1910
(c) 1915
(d) 1913
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1913
34. Bohr considered ———-atom as a model.
(a) Helium
(b) Hydrogen
(c) Thorium
(d) None of these
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Hydrogen
35. Electrons are revolving around the fixed circular path called ————-.
(a) Shells
(b) Orbits
(c) cycles
(d) Both a and b
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Both a and b
36. Each shell has a —————– energy.
(a) Fixed
(b) variable
(c) No
(d) None of these
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Fixed
37. The farther the electron from the nucleus, the ———— will be the energy and vice versa.
(a) Lower
(b) Higher
(c) Intermediate
(d) None of these
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Higher
38. The ________ of an object is fixed.
(a) Frequency
(b) Volume
(c) Energy
(d) None of these
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Energy
39. ∆E=E_2-E_1=h \mu In ths equation what is “h”?
(a) Plank’s constant
(b) Max constant
(c) Variable
(d) None of these
Show Answer
Plank’s constant
40 Electrons can’t stay in ———shells.
(a) 1st
(b) 2nd
(c) Between
(d) None of these
Show Answer
Between
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Fundamental Particles of an atom
Electron
Proton
Neutron
41. Modern research show that an atom consist of ————— subatomic particles.(a) 13
(b) 03
(c) 05
(d) None of these
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03
42. Election is ————— charged particle.
(a) Negatively
(b) Positively
(c) Neutral
(d) All of these
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Negatively
43. Mass of electron is ————–.
(a) 9.11 \times 10^{31} kg
(b) 9.11 \times 10^{-31} kg
(c) 6.023 \times 10^{23} kg
(d) All of these
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9.11 \times 10^{-31} kg
44. Proton is a ———— charged particle.
(a) Negatively
(b) Positively
(c) Neutral
(d) None of these
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Positively
45. Mass of proton is —————.
(a) 1.6726 \times 10^{-27} \ kg
(b) 9.11 \times 10^{-31} \ kg
(c) 1.37 \times 10^6 \ kg
(d) All of these
Show Answer
1.6726 \times 10^{-27} \ kg
46. Proton is ———– times heavier than electron.
(a) 1847
(b) 1827
(c) 1837
(d) All of these
Show Answer
1837
47. Neutron is a ————- particle because it has no charge.
(a) Negative
(b) Positive
(c) Neutral
(d) None of these
Show Answer
Neutral
48. Neutron is ———– times Havier than proton.
(a) 05
(b) 15
(c) 50
(d) 150
Show Answer
05
Electronic Configuration
Energy Level
s and p Sub-Shell
Shell (Orbit)
Sub-Shell
49. The ———— of electrons around the nucleus in shells is called electronic configuration.(a) Separation
(b) Distribution
(c) Catenation
(d) None of these
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Distribution
50. These shells are represented by ————.
(a) Alphabets
(b) Numeric
(c) Romans
(d) None of these
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Alphabets
51. The maximum number of electrons in a particular shell is given by the formula ————.
(a) 4n^2
(b) 2n^3
(c) 4n^3
(d) 2n^2
Show Answer
2n^2
52. How many electrons are there K-shell?
(a) 2
(b) 8
(c) 18
(d) 32
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2
53. How many electrons are there in L-shell?
(a) 2
(b) 8
(c) 18
(d) 32
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8
54. How many electrons are there in M-shell?
(a) 2
(b) 8
(c) 18
(d) 32
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18
55. How many electrons are there in N-shell?
(a) 2
(b) 8
(c) 18
(d) 32
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32
56. A shell or orbit is also is also called ———–.
(a) Energy level
(b) Hertz
(c) Atomic mass
(d) None of these
Show Answer
Energy level
57. How many sub-shall are there in a shell?
(a) 14
(b) 10
(c) 04
(d) None of these
Show Answer
04
58. Which of them are sub-shell?
(a) s, p, d, f
(b) x, y, z
(c) K, L, M, N
(d) None of these
Show Answer
s, p, d, f
59. “s” sub –shell stands for ————-.
(a) Specific
(b) Sharp
(c) Sonic
(d) All of these
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Sharp
60 “p” sub-shell stands for —————
(a) Principal
(b) principle
(c) Para-magnetic
(d) None of these
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Principal
61 “d” sub –shell stands for ————-.
(a) Drainage
(b) dissolved
(c) diffused
(d) All of these
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diffused
62. “f” sub-shell stand for———–.
(a) Fermium
(b) fundamental
(c) Fencing
(d) None of these
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fundamental
63. “f” sub-shell can accommodate————- electrons.
(a) 2
(b) 6
(c) 10
(d) 14
Show Answer
14
64. Complete the electronic configuration of carbon atom i.e. 1s^2, 2S^2, ————-.
(a) 2p^2
(b) 2p^3
(c) 2p^4
(d) 2p^5
Show Answer
2p^2
Isotopes
65. Atoms of the same element having same atomic number but different ———– is called isotopes.(a) Density
(b) Mobility
(c) Mass number
(d) None of these
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Mass number
66. Atoms having same number of protons and electrons but differ number of neutrons are called ———–.
(a) Metallurgy
(b) Isotopes
(c) Surface area
(d) None of these
Show Answer
Isotopes
Isotopes of Hydrogen
67. How many isotopes hydrogen has?(a) 03
(b) 06
(c) 09
(d) 12
Show Answer
03
68. Protium, deuterium and tritium are the isotopes of ————-.
(a) carbon
(b) chlorine
(c) Hydrogen
(d) None of these
Show Answer
Hydrogen
69. What is the most abundant isotope of hydrogen?
(a) Protium
(b) Deuterium
(c) tritium
(d) None of these
Show Answer
Protium
70. Which isotope of hydrogen is rarely found in nature?
(a) Protium
(b) Deuterium
(c) Tritium
(d) None of these
Show Answer
Tritium
71. How many neutrons are there in tritium?
(a) 02
(b) 03
(c) 01
(d) None of these
Show Answer
02
Isotopes of Carbon
72. Atomic number of carbon is ————-.(a) 07
(b) 06
(c) 08
(d) None of these
Show Answer
06
73. Carbon is the first member of ————–.
(a) Group 1
(b) Group 7
(c) Group 4
(d) Group 6
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Group 4
74. How many isotopes of carbon are there in nature?
(a) 03
(b) 13
(c) 07
(d) 14
Show Answer
03
75. C -12, C -13 \ and \ C -14 are the isotopes of ————–.
(a) Iodine
(b) Radon
(c) Carbon
(d) none
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carbon
76. Number of neutrons in Carbon-14 \ \left(_{14}C^6 \right) is —————.
(a) 7
(b) 8
(c) 9
(d) 10
Show Answer
8
Isotopes of Chlorine
77. Atomic number of chlorine is ——————–.(a) 17
(b) 6
(c) 1
(d) 3
Show Answer
17
78. Chlorine is the second member of ————-
(a) Group 1
(b) Group 4
(c) Group 7
(d) Group 5
Show Answer
Group 7
79. Group 7is also called ————-
(a) Alkali metals
(b) Halogens
(c) Nobles
(d) none
Show Answer
Halogens
80. How many isotopes of chlorines are there in nature?
(a) 02
(b) 12
(c) 03
(d) 13
Show Answer
02
81. Cl -35 \ and \ Cl-37 are isotopes of ————–.
(a) Radon
(b) Krypton
(c) Chlorine
(d) Hydrogen
Show Answer
Chlorine
82. The abundance of Cl -35 is —————-.
(a) 75.53%
(b) 53.75%
(c) 73.55%
(d) 53. 66%
Show Answer
75.53%
83. The abundance of Cl-37 is————- in nature.
(a) 24.47%
(b) 47.24%
(c) 74. 42%
(d) 54.26%
Show Answer
24.47%
84. The number of neutrons in Cl-35 is 18 and Cl-37 is —————-.
(a) 20
(b) 40
(c) 02
(d) 04
Show Answer
20
Isotopes of Uranium
85. Atomic number of uranium is —————.(a) 82
(b) 92
(c) 28
(d) 29
Show Answer
92
86. How many isotopes of uranium in nature?
(a) 07
(b) 05
(c) 03
(d) 04
Show Answer
03
87. The most abundant isotope of uranium is —————.
(a) U -238
(b) U-235
(c) U-234
(d) U-236
Show Answer
U -238
88. The neutrons quantity in U-238 is ————–.
(a) 142
(b) 146
(c) 143
(d) 145
Show Answer
146
Uses of Isotopes
89. Iodine -131 is used for the cure of ————-.(a) Pneumonia
(b) Cancer
(c) Goiter
(d) None of these
Show Answer
Goiter
90. Cobalt -60 is used for the treatment of —————-.
(a) Cancer
(b) Diarrhea
(c) Tumor
(d) Treat less
Show Answer
Cancer
91. Carbon -14 is used to trace the path of carbon in ————–.
(a) Respiration
(b) Photosynthesis
(c) Reduction
(d) None of these
Show Answer
Photosynthesis
92. Californium -252 is used to inspect airplane luggage for hidden —————-.
(a) Explosives
(b) Smoke detectors
(c) Carbon tracing
(d) None of these
Show Answer
Explosives
Review Exercise Chapter 2
93. The maximum number of electrons in third energy level is:(a) 10
(b) 32
(c) 18
(d) 64
Show Answer
18
94. Mass of an atom is mostly due to its
(a) Nucleus
(b) Neutrons
(c) Electrons
(d) Protons
Show Answer
Nucleus
95. If Rutherford had used neutrons instead of alpha particles in his scattering experiment, the neutrons would
(a) Not deflect because they have no charge
(b) Have deflected more often
(c) Have been attracted to the nucleus easily
(d) Have given the same results
Show Answer
Not deflect because they have no charge
96. Electron in its ground state does not
(a) Spin
(b) Revolve
(c) Radiate energy
(d) Reside in orbit
Show Answer
Radiate energy
97. Which statement about _6^{12}X \ and \ _6^{14}Y is false except
(a) They are isotopes
(b) They are the same elements
(c) They have the same number of electrons
(d) They have the same number of neutrons
Show Answer
They have the same number of electrons
98. The neutron particle
(a) Has a mass equal to that of an electron
(b) Has a mass approximately equal to that of a proton
(c) Has charge equal to but opposite to that of an electron
(d) Has a positive charge
Show Answer
Has a mass approximately equal to that of a proton
99. Isotopes of the same element have
(a) The same number of protons
(b) The same number of neutrons
(c) Different number of electrons
(d) The same mass number
Show Answer
The same number of protons
100. Which one is the lightest?
(a) An alpha particle
(b) A hydrogen atom
(c) An electron
(d) A proton
Show Answer
An electron
101. The nucleus of an atom has all of the following Characteristics except that
(a) Is positively charged
(b) Is very dense
(c) Contains nearly all of the atom’s mass
(d) Contains nearly all of the atom’s volume
Show Answer
Contains nearly all of the atom’s volume
102. L – shell has sub – shell (s)
(a) s
(b) s and p
(c) s, p, and d
(d) s, p, d and f
Show Answer
s and p
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