Q60. In the Gold foil experiment of Geiger and Marsden, that paved the way for Rutherford’s model of an atom, ~ 1.00% of the α-particles were found to deflect at angles > 50°. If one mole of a-particles were bombarded on the gold foil, compute the number of α-particles that would deflect at angles less than 50°.

 

Q61. The ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is 14. What is the number of electrons in the ion?

(a) 13      (b) 10      (c) 14     (d) 16

 

Q62. Compare the properties of electrons, protons and neutrons.

 

Q63. What are the limitations of J.J. Thomson’s model of the atom?

 

Q64. Write the distribution of electrons in carbon and sodium atoms.

 

Q65. Describe Bohr’s model of the atom. 

 

Q66. Show diagrammatically the electron distributions in a sodium atom and a sodium ion and also give their atomic number.

 

Q67. Identify the Mg2+ ion from the figure where, n and p represent the number of neutrons and protons respectively.


 

Q68. What are the postulates of Bohr’s model of an atom?

 

Q69. Enlist the conclusions drawn by Rutherford from his a-ray scattering experiment.

 

Q70. In what way is the Rutherford’s atomic model different from that of Thomson’s atomic model?

 

Last modified: Tuesday, 1 June 2021, 6:34 PM