UP Board Class 9 Science Chapter 4 Structure Of The Atom Multiple Choice Questions

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Structure Of The Atom Multiple Choice Questions

UP Board Class 9 Science Chapter 4 Structure Of The Atom Multiple Choice Questions

Question 1. The cathode ray experiment was done for the first time by

  1. Goldstein
  2. J. J. Thomson
  3. Dalton
  4. Rutherford

Answer: 2. J. J. Thomson

J. J. Thomson, his first experiment was to build a cathode ray tube with a metal cylinder on the end.

Question 2. By whom was neutron discovered

  1. J. Chadwick
  2. Dalton
  3. Bohr
  4. Rutherford

Answer: 1. J. Chadwick

Neutron is another sub-atomic particle, discovered by J. Chadwick in 1932, It is represented by n. Neutrons are electrically neutral particles.

Question 3. 1H1 is named (termed) as

  1. Protium
  2. Deuterium
  3. Tritium
  4. Proton

Answer: 1. Protium

The name of the 1H1 is the protium.

Question 4. Which class is near the nucleus of the atom?

  1. K-class (shell)
  2. L-class (shell)
  3. M-class (shell)
  4. N-class (shell)

Answer: 1. K-class (shell)

K-class (shell) is the nearest the nucleus of the atom.

Question 5. How many neutrons are present in the nucleus of a hydrogen atom?

  1. 1
  2. 2
  3. 3
  4. 0

Answer: 4. 0

There are no neutrons in the nucleus of the hydrogen atom, hence mass number of hydrogen atoms is zero.

Question 6. Which one of the following elements has a 2, 8, 13, 1 electronic configuration?

  1. Chromium
  2. Copper
  3. Silver
  4. Palladium

Answer: 1. Chromium

The real electronic configuration of chromium is 2, 8, 13, 1 but according to Bohr, it’s 2, 8, 12, 2.

Question 7. The number of valence electrons present in Mg2+ ions is

  1. 16
  2. 8
  3. 17
  4. 18

Answer: 2. 8

Valency means several electrons are present in the outer shell.

For 12Mg(atom) =2, 8, 2, valence electrons = 7 But i2Mg+ 2 (ion) = 2, 8 valence electrons = 8

Question 8. Which of the following is the valency of an element, it has 2, 8, 2 electronic configurations.

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

Answer: 1. 2

The valency of an element is 2 because two electrons are present in the outer shell.

Question 9. Which one of the following is the electronic configuration of sodium?

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

Answer: 4. 2, 8, 1

The atomic number of sodium is 11. So, electronic configuration 11N = 2, 8,1.

Question 10. The isotope used in the treatment of goiter is

  1. U-235
  2. Iodine (I-131)
  3. Co-60
  4. Na-24

Answer: 2. Iodine (1-131)

An isotope of iodine (1-131) is used in the treatment of goiter.

Question 11. The nucleons are

  1. Electrons are protons
  2. Protons and neutrons
  3. Electrons and neutrons
  4. None of these

Answer: 2. Electrons are protons

Question 12. In Ruther Ford’s experiment a-particles were deflected because of

  1. Electrostatic attraction between y particles and positively charged part of an atom
  2. Electrostatic repulsion between particles and the positively charged part of an atom
  3. Electrostatic repulsion between p-particles and positively charged part of an atom
  4. None of these

Answer: 2. Electrostatic repulsion between particles and the positively charged part of an atom

Question 13. The properties of an atom depends on

  1. Number of protons
  2. Number of neutrons
  3. Atomic mass
  4. Electronic structure

Answer: 4. Electronic structure

Question 14. Which one of the following is free of charge?

  1. Electron
  2. Proton
  3. Neutron
  4. None of the above

Answer: 3. Neutron

Question 15. The atomic number of sodium is 11 and its mass number is 23. It has

  1. 12 protons and 11 electrons
  2. 11 neutrons and 12 protons
  3. 11 electrons and 12 neutrons
  4. 12 electrons and 11 neutrons

Answer: 3. 11 electrons and 12 neutrons

Question 16. The mass of the nucleus is

  1. Number of protons in the nucleus
  2. Number of neutrons in the nucleus
  3. Number of nucleons in the nucleus
  4. None of these

Answer: 3. Number of nucleons in the nucleus

Question 17. The isotope used to remove brain tumors and treatment of cancer is

  1. U-235
  2. iodine
  3. Co-60
  4. Na-24

Answer: 3. Co-60

Question 18. Among the following is an element of electronic configuration

  1. 2, 8
  2. 2, 6
  3. 2, 8, 18
  4. 2, 8, 1

Answer: 2. 2, 6

Question 19. 8016, 8017, and 8018 are known as

  1. Equilibrium
  2. Even factor
  3. Isotope
  4. None of these

Answer: 3. Isotope

Question 20. Which of the following has the largest (maximum) number of isotopes?

  1. Polonium
  2. Hydrogen
  3. Uranium
  4. Lead

Answer: 1. Polonium

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