WBBSE For Class 9 Physical Science And Environment Atomic Structure MCQS

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Atomic Structure MCQs

Question 1. The smallest part of an element that retains the chemical properties of the element is

  1. Electron
  2. Molecule
  3. Atom
  4. Proton

Answer: (4) Proton

Question 2. Electron was discovered by

  1. William Crookes
  2. A. Arrhenius
  3. Michael Faraday
  4. J. J. Thomson

Answer: (4) J. J. Thomson

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. Cathode rays are composed of

  1.  Radiation
  2. Thermal radiation
  3.  Beam of negatively charged particles
  4.  Positively charged particles

Answer: (3) Beam of negatively charged particles

WBBSE For Class 9 Physical Science And Environment Atomic Structure MCQS

WBBSE Class 9 atomic structure MCQs with answers

Question 4. Cathode rays are deflected under the influence of electromagnetic fields because cathode rays are

  1.  Electromagnetic radiation (EMR, i-e., light)
  2. Positively charged particles
  3. Beam of neutral particles
  4. Beam of electrons

Answer: (4) Beam of electrons

Question 5. In a perforated cathode ray tube, other rays other than cathode rays were found. These rays are

  1. Protons
  2. Electrons
  3. Radiation
  4. Neutrons

Answer: (3) Radiation

Question 6. Who among the following got Nobel Prize twice?

  1. Rutherford
  2. Bohr
  3. Einstein
  4. Marie Curie

Answer: (4) Marie Curie

Question 7. Radioactivity was discovered by

  1. Rutherford
  2. Becquerel
  3. Marie Curie
  4. Pierre Curie

Answer: (3) Marie Curie

Atomic structure multiple choice questions for WBBSE Class 9

Question 8. Radioactivity was first recognised while working with which element?

  1. Uranium
  2. Thorium
  3. Polonium
  4.  Barium

Answer: (1) Uranium

Question 9. The concept of nucleus of an atom was given by

  1. J. J. Thomson
  2. Neils Bohr
  3.  Rutherford
  4. M. Curie

Answer: (3) Rutherford

Question 10. The diameter of the nucleus is of the order of

  1. 10–3cm
  2. 10–23cm
  3. 10–3 cm
  4. 10–13 cm

Answer: (4) 10–13 cm

Question 11. From the fact that a helium atom is four times as heavy as a. hydrogen atom, Rutherford predicted the existence of

  1. Proton
  2. Isotope
  3. Neutron
  4. Nucleus

Answer: (1) Proton

Important atomic structure questions for Class 9 Physical Science

Question 12. From the study of sun spectra, the element first identified is

  1.  Helium
  2. Hydrogen
  3. Uranium
  4. Gold

Answer: (1) Helium

Question 13. Which of the following concepts is not connected to Bohr’s model?

  1. Circular shell or orbit
  2. Quantization
  3.  Line spectra of hydrogen
  4. Nuclear force

Answer: (2) Quantization

Question 14. An electron in a Bohr’s orbit is associated with definite

  1. Radius
  2. Velocity
  3. Energy
  4. All of the above

Answer: (3) Energy

Question 15. lonization energy of hydrogen atom, as calculated (by Bohr) and experimentally obtained, is

  1. 13.56 eV
  2. 13.56 J
  3. 13.56 Cal
  4. None of these

Answer: (1) 13.56 eV

WBBSE Class 9 Physical Science MCQs on atom models

Question 16. Which of the following is considered as a limitation of Bohr’s model? It wa unable to explain

  1. En , ie., energy of the nth shell electron of hydrogen
  2. Ionization energy of hydrogen
  3.  Line spectrum of helium
  4. Line spectrum of hydrogen

Answer: (2) lonization energy of hydrogen

Question 17. On which of the following, Rutherford’s model differs from Bohr’s model?

  1. Circular shape of orbit
  2. Concept of the nucleus
  3. Empty space in an atom
  4. Stability of an atom

Answer: (4) Stability of an atom

Question 18. Which of the following is true?
(A = mass number, Z = atomic number, N = number of neutrons)

  1. A= Z
  2. A=Z-N
  3. A=Z+N
  4.  A=N-Z

Answer: (3) A=Z+N

Question 19. Isotopes of an element have the same

  1. Mass number (A)
  2. Number of neutrons
  3. Number of protons
  4. Number of protons but not electrons

Answer: (3) Number of protons

Solved MCQs on atomic structure for WBBSE Class 9

Question 20. Isotopes are atoms with same number of

  1. Neutrons
  2. Protons
  3. Electrons
  4. Protons

Answer: (1) Neutrons

Question 21. Isobars are atoms having same number of

  1. Protons
  2. Nettvons
  3. Electrons
  4. Protons + Neutrons

Answer: (4) Protons + Neutrons

Question 22. Mass of a 12C isotope, in AMU unit is,

  1.  4
  2. 12
  3. 1/12
  4. None of them

Answer: (2) 12

Question 23. The ground state electron configuration of potassium (Z = 19) is

  1. 2, 8, 8, 1
  2. 2, 8, 9,0
  3.  2, 9, 8, 0
  4. 2,7, 8, 2

Answer: (1) 2, 8, 8, 1

Question 24: Atoms of which element have no neutron?

  1. Oxygen
  2. Hydrogen
  3. Carbon
  4. Nitrogen

Answer: (2) Hydrogen

Bohr’s model and Rutherford’s model MCQs Class 9 WBBSE

Question 25. Which force binds the nucleons?

  1. Gravitational force
  2. Electrostatic force
  3. Nuclear force
  4.  None of these

Answer: (3) Nuclear force

Question 26. Which scientist first enunciated the atomic concept of matter?

  1. Newton
  2.  Einstein
  3. Dalton
  4. None of these

Answer: (3) Dalton

Question 27. The atomic number is

  1. Mass of an atom x
  2. Total number of protons and neutrons
  3. Number of protons
  4. Number of neutrons

Answer: (3) Number of protons

Question 28. The maximum possible number of electrons in the outermost shell of an atom is

  1. 16
  2. 18
  3.  8
  4. 10

Answer: (3) 8

29. The magnitude of the negative charge an electron carries is

  1. 1.602 x 10–2 coulombs
  2. 0.602 x 10 –9 coulombs
  3. 1.602 x 10–19 coulombs
  4.  1.602 x 10–25 coulombs

Answer: (3) 1.602 x 10–19 coulombs

Question 30. If two isotopes of a certain element are known, it follows: that the atoms of the element

  1. Differ chemically frorn each other
  2. Have different numbers of electrons surrounding their nucle.
  3. Have different numbers of neutrons in their nuclei.
  4.  Have the same mass number.

Answer: (3) Have different numbers of neutrons in their nuclei.

Best multiple-choice questions on atomic structure for WBBSE Class 9

Question 31. Which of the following are examples of isotopes

  1. 14C and , 14N
  2. 40K and, 40Ca
  3. 8 16O and 8 18O
  4. None of these

Answer: (3) 8 16O and, 8 18O

Question 32. Sodium atom forms a cation by losing one electron. The cation will be 

  1. S+
  2. Na+
  3.  Kt+
  4. None of these

Answer: (2) Na+

Question 33. A deuteron contains

  1. A neutron and position
  2. A neutron and a proton
  3. A neutron and two protons
  4. A proton and two neutrons

Answer: (2) A neutron and a proton

Question 34. The nucleus of an atom contains

  1. Electrons
  2. Protons alone
  3. Neutrons alone
  4. Protons and neutrons

Answer: (4) Protons and neutrons

Question 35. The neutron was discovered by

  1. J .J. Thomson
  2.  G. T. Seaborg
  3. E. Rutherford
  4. James Chadwick

Answer: (4) James Chadwick

Question 36. The number of electrons in the nucleus of 6C12 is

  1. 6
  2. 12
  3. 0
  4. 3

Answer: (3) 0

Question 37. Positron is

  1. _1 0e
  2. +10e
  3.   11H
  4.  None of these

Answer: (2)  +10e

WBBSE Class 9 Physical Science subatomic particles MCQs

Question 38. The average distance of an electron in an atom from its nucleus is of the order of 

  1. 106m
  2. 10–6m
  3. 10–10m
  4. 10–15m

Answer: (3) 10–10 m

Question 39. A neutral atom (atomic no. > 1) contains

  1.  Proton only
  2. Neutron + Proton
  3. Neutron + Electron
  4. Neutron + Proton + Electron

Answer: (4) Neutron + Proton + Electron

Question 40. The radius of an atom is of the order of

  1. 10–10cm
  2. 10–13cm
  3. 10–15cm
  4.  10–8cm

Answer: (4) 10–8 cm

Question 41. Chlorine atom differs from chlorine ion in the number of which of the following ?

  1. Protons
  2. Neutrons
  3. Electrons y
  4.  Both Protons and Neutrons

Answer: (3) Electrons

Question 42. Neutrons are present inthe nuclei of all elements except

  1. Hydrogen
  2. Oxygen
  3. Deuterium
  4. Chlorine

Answer: (1) Hydrogen

Question 43. When electrons revolve in stationary orbits 

  1. There is no change in energy level
  2. They become stationary
  3. They are gaining kinetic energy
  4. There is increase in energy

Answer: (1) There is no change in energy level

Question 44. Which of the following isoelectronic species has less electrons than protons?

  1. O2-
  2.  F–
  3. Na+
  4. Mg2+

Answer: (1) O2-

Question 45. As we move away from the nucleus, the energy of an orbit

  1. Decreases
  2. Increases
  3. Remains unchanged
  4. None of these

Answer: (2) Increases

Question 46. By addition of one electron in the outermost shell of a chlorine atom, it produces a

  1. New atom
  2. Anion
  3. Cation
  4. No change

Answer: (2) Anion

Question 47. Nucleons are

  1. Only protons
  2. Only neutrons
  3.  Protons and neutrons
  4. Protons, electrons and neutrons

Answer: (3) Protons and neutrons

Question 48. Rutherford’s a-particle scattering experiment led to the discovery of

  1. Electrons
  2. Protons
  3. Neutrons
  4. Atomic nucleus

Answer: (4) Atomic nucleus

Question 49. The electronic configuration of a sodium atom is

  1.  2, 8, 3
  2. 2, 8, 8
  3.  2, 8, 1
  4. 2,5, 3

Answer: (3) 2, 8, 1

Question 50. The valency of the element having electronic configuration 2, 8, 8, 1 is

  1. 1
  2. 2
  3.  3a
  4. 7

Answer: (1) 1

 

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