CBSE Class 9 Science Structure of atom Sure Shot Questions A

CBSE Class 9 Science Structure of atom Sure Shot Questions A. There are many more useful educational material which the students can download in pdf format and use them for studies. Study material like concept maps, important and sure shot question banks, quick to learn flash cards, flow charts, mind maps, teacher notes, important formulas, past examinations question bank, important concepts taught by teachers. Students can download these useful educational material free and use them to get better marks in examinations.  Also refer to other worksheets for the same chapter and other subjects too. Use them for better understanding of the subjects.

1. Plum pudding Model of atom was discovered by _______________

2. Combining capacity of an atom is called _______________

3. Alpha - particle scattering experiment of Rutherford led to discovery of _________

4. Number of neutrons in 81 /35Br is _____________

5. __________ are atoms having the same mass number but different atomic number.

6. The charge on the electron is found to be ________ coulombs.

7. The electronic configuration of silicon is ___. (Atomic number = 14)

8. _____ electrons are responsible for the chemical properties of an atom.

9. Rutherford’s model of an atom was modified by _______.

10. ____ is an isotope of carbon used in determining the age of dead plants.

11. An atom with 3 protons and 4 neutrons will have a valency of _________.

12. What do you understand by valency of an element? What is valency of boron?

13. List the features of Rutherford's nuclear model of atom.

14. What are the postulates of Bohr Model of an atom?

15. Define Valency. What is the valency of chlorine, sulphur and magnesium?

16. Cl^- has completely filled K&L shells. Explain.

17. Na⁺ is possible but Cl^{+ i}s not possible. What is the reason?

18. What are isotopes? Give two examples .

19. What were the observations of Rutherford's Alpha particles scattering experiment?

20. What are the drawbacks of Rutherford's model of atom?

21. From what observations do you derive the following inferences?

(i) The most of the space inside the atom is empty.

(ii) The volume of the nucleus is very small.

(iii) Anode rays consist of positively charged particles.

22. Name the fundamental particle not present in the nucleus of hydrogen atom

23. Who discovered electrons?

24. Who discovered protons?

25. Who discovered neutrons?

26. Who discovered nucleus of an atom?

27. What are canal rays?

28. What are the properties of anode rays?

29. What are cathode rays?

30. Who discovered X-Rays?

31. If an atom contains one electron and one proton, will it carry any charge or not?

32. Complete the following table.

Particle Electron             Proton                Neutron
(i) Symbol _______      _______              _______
(ii) Nature _______       _______             _______
(iii) Relative Charge _______ _______     _______
(iv) Absolute Charge _______ _______    _______
(v) Relative Mass _______ _______         _______
(vi) Absolute Mass _______ _______       _______

33. What is the mass of proton as compared to electron?

34. Describe briefly Thomson's model of an atom.

35. Write the limitations of J.J. Thomson's model of an atom.

36. What are α-particles?

37. On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?

38. Who is known as 'Father of Nucleus Physics'?

39. What were the observations of Rutherford's α-scattering experiment?

40. What were the important features of atomic model based on Rutherford's scattering experiment?

41. What are the limitations of Rutherford’s model of the atom?

42. Draw a sketch of Bohr’s model of an atom with three shells.

43. Describe Bohr’s model of the atom.

44. What do you think would be the observation if the α-particle scattering experiment is carried out using a foil of a metal other than gold?

45. Write a short note on Nucleus.

46. What is Atomic Number? Who coined this term?

47. What is mass number?

48. If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?

49. What is ionization energy?

50. In a sample of ethyl ethanoate (CH3COOC2H5) the two oxygen atoms have the same number of electrons but different number of neutrons. What can be the reason for it?

51. In the atom of element X, 6 electrons are present in the outermost shell. If it requires an octet configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?

52. Why do helium, neon & argon have a zero valency?

53. Write the atomic number and the symbol of an element which has mass number 32 and the number of neutrons 16 in the nucleus.

54. Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

55. If number of electrons in an atom is 8 and number of protons is also 8,then (i) what is the atomic number of the atom? (ii) what is the charge on the atom?

56. What are the limitations of J. J. Thomson's model of the atom?

57. Why was Thomson's model of atom discarded and replaced by Rutherford's model? Why is Rutherford's model also called the nuclear model of atom

58. The average atomic mass of a sample of an element X is 16.2u. What are the percentage of isotopes 16 18 8 X and 8 X in the sample?

59. What are the salient feautres of Bohr's Atomic Model? How is it advantageous over Rutherford's Nuclear Model?

60. What is the charge and mass of the anode rays emitted when, hydrogen gas is enclosed in the discharge tube experiment? What is the name of these particles?

61. Do the anode rays always consist of protons whatever be the gas enclosed in the discharge tube? Explain.

62. What is the other name of X-rays?

63. How are x-rays produced? Why was this name given?

64. How are x-rays made tools in diagnostic purposes in the medical field?

65. What is phosphorescence? How does it differ from fluorescence?

66. Who discovered the nuclear model of the atom?

67. Explain how Rutherford’s atomic structure cannot explain the stability of atom?

68. Explain how Bohr’s atomic model explains the emission and absorption of radiation.

69. What is the charge and mass of a β-particle? From which part of the atom are β-particles emitted?

70. The two elements, A and B have 17 electrons each in their atom. Element A has 35 nucleons while element B has 33 nucleons (nucleons are the total number of protons and

neutrons in the nucleus). What is the relationship between these two elements? Explain. The element A reacts with hydrogen in diffused light. Does the element B also react with hydrogen?

71. One isotope of carbon with atomic mass 12, occupies group 14 in the 2nd period in the long form periodic Table. Predict the position of another radioactive isotope of carbon with atomic mass 14?

72. What is the name given to the rays, traveling from cathode to anode?

73. Do the cathode rays always consist of electrons only, whatever be the gas enclosed in the discourage tube?

74. Why are electrons in the outermost shell known as valence electrons?

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