Class 9 chemistry MCQs with answers are provided here for chapter 4 Structure of the Atom. These MCQs are based on the CBSE board curriculum and correspond to the most recent Class 9 chemistry syllabus. By practicing these Class 9 Multiple choice questions, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 9 Annual examinations as well as other entrance exams such as CTET and KVS. Here are 30 multiple-choice questions based on the chapter "Atomic Structure" for Class 9 CBSE board syllabus:
1. Who discovered the electron?
a) J.J. Thomson
b) Ernest Rutherford
c) John Dalton
d) Niels Bohr
2. The atomic number of an element is determined by the number of:
a) Electrons
b) Neutrons
c) Protons
d) Nucleons
3. The nucleus of an atom is composed of:
a) Protons and neutrons
b) Electrons and neutrons
c) Protons and electrons
d) Electrons and nucleons
4. The mass number of an atom is the sum of:
a) Protons and neutrons
b) Electrons and neutrons
c) Protons and electrons
d) Electrons and nucleons
5. The model of the atom proposed by Bohr resembles:
a) A plum pudding
b) A planetary system
c) A rigid sphere
d) A nucleus surrounded by electrons randomly
6. Which subatomic particle carries a negative charge?
a) Proton
b) Neutron
c) Electron
d) Nucleus
7. The total number of electrons that can be accommodated in the first shell of an atom is:
a) 2
b) 8
c) 18
d) 32
8. Isotopes of an element have the same number of:
a) Protons
b) Electrons
c) Neutrons
d) Nuclei
9. The number of protons present in the nucleus of an atom is called:
a) Atomic mass
b) Atomic number
c) Mass number
d) Neutron number
10. The atomic mass of an element is determined by the number of:
a) Protons
b) Electrons
c) Neutrons
d) Nucleons
11. The subatomic particle that determines the chemical properties of an element is the:
a) Proton
b) Neutron
c) Electron
d) Nucleus
12. The number of neutrons in an atom can be calculated by subtracting the ______ from the mass number.
a) Atomic number
b) Electron number
c) Proton number
d) Nucleon number
13. The symbol "X" in the notation (A/ZX) represents the:
a) Atomic number
b) Atomic mass
c) Mass number
d) Chemical symbol of the element
14. The number of electrons in the outermost shell of an atom determines its:
a) Atomic number
b) Valency
c) Atomic mass
d) Mass number
15. The maximum number of electrons that can be accommodated in the second shell of an atom is:
a) 2
b) 8
c) 18
d) 32
16. Who proposed the model of the atom known as the "Plum Pudding" model?
a) J.J. Thomson
b) Ernest Rutherford
c) Niels Bohr
d) John Dalton
17. The particles that revolve around the nucleus of an atom are:
a) Electrons
b) Protons
c) Neutrons
d) Nuclei
18. The number of protons in an atom is equal to the:
a) Atomic mass
b) Atomic number
c) Mass number
d) Neutron number
19. The mass of an electron is approximately equal to:
a) 1.67 x 10⁻²⁷ kg
b) 9.11 x 10⁻³¹ kg
c) 1.67 x 10⁻²⁷ g
d) 9.11 x 10⁻³¹ g
20. The particles that determine the mass of an atom are:
a) Electrons
b) Protons
c) Neutrons
d) Nuclei
21. The number of protons in the nucleus of an atom is also equal to the number of:
a) Electrons in the nucleus
b) Neutrons in the nucleus
c) Nucleons in the nucleus
d) Electrons outside the nucleus
22. The Bohr model failed to explain the:
a) Stability of atoms
b) Formation of ions
c) Energy levels of electrons
d) Dual nature of electrons
23. The total number of electrons that can be accommodated in the third shell of an atom is:
a) 2
b) 8
c) 18
d) 32
24. The atomic number of an element is also equal to the number of:
a) Protons in the nucleus
b) Electrons in the nucleus
c) Neutrons in the nucleus
d) Nucleons in the nucleus
25. The Rutherford gold foil experiment established the presence of:
a) Protons
b) Neutrons
c) Electrons
d) Nuclei
26. Which subatomic particle is responsible for radioactivity?
a) Proton
b) Neutron
c) Electron
d) Nucleus
27. The number of protons in an atom is responsible for its:
a) Atomic mass
b) Atomic number
c) Mass number
d) Neutron number
28. The mass of a proton is approximately equal to:
a) 1.67 x 10⁻²⁷ kg
b) 9.11 x 10⁻³¹ kg
c) 1.67 x 10⁻²⁷ g
d) 9.11 x 10⁻³¹ g
29. The number of electrons in an atom is equal to the number of:
a) Protons in the nucleus
b) Neutrons in the nucleus
c) Nucleons in the nucleus
d) Protons outside the nucleus
30. The number of electrons in an atom is also equal to the number of:
a) Nuclei in the atom
b) Protons in the atom
c) Neutrons in the atom
d) Nucleons in the atom
Answers:
1. a) J.J. Thomson
2. c) Protons
3. a) Protons and neutrons
4. a) Protons and neutrons
5. b) A planetary system
6. c) Electron
7. a) 2
8. c) Neutrons
9. b) Atomic number
10. c) Neutrons
11. c) Electron
12. d) Nucleon number
13. d) Chemical symbol of the element
14. b) Valency
15. b) 8
16. a) J.J. Thomson
17. a) Electrons
18. b) Atomic number
19. b) 9.11 x 10⁻³¹ kg
20. c) Neutrons
21. d) Electrons outside the nucleus
22. a) Stability of atoms
23. c) 18
24. a) Protons in the nucleus
25. d) Nuclei
26. b) Neutron
27. b) Atomic number
28. c) 1.67 x 10⁻²⁷ g
29. d) Protons outside the nucleus
30. b) Protons in the atom
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