Class 9th Chemistry Unit 2 Structure of Atoms

chemistry 9th notes Chapter No 2

1. Rutherford used a gold foil in his experiment, which had a thickness of:

 
 
 
 

2. Chlorine has isotopes:

 
 
 
 

3. The concept of orbit was used by:

 
 
 
 

4. Who predicted in 1920 that some neutral particles having mass equal to that of proton are present in an atom?

 
 
 
 

5. How many electrons can be accommodated by M-shell?

 
 
 
 

6. Electronegativity of elements ________in a group.

 
 
 
 

7. Which one of the following results in the discovery of proton?

 
 
 
 

8. Which one is radioactive isotope?

 
 
 
 

9. The nucleus of an atom is composed of:

 
 
 
 

10. When U-235 breaks up, it produces:

 
 
 
 

11. Which one of the following shell consists of three sub-shells.

 
 
 
 

12. Rutherford bombarded alpha particles on a gold foil having thickness:

 
 
 
 

13. How many subshells are there in M-shell?    

 
 
 
 

14. Which subshells are present in L-shell?

 
 
 
 

15. Electronic configuration of oxygen is:

 
 
 
 

16. Electronic configuration of Neon is:

 
 
 
 

17. The angular momentum of an electron moving in a circular orbit is:

 
 
 
 

18. Plum pudding theory was put forward by:    

 
 
 
 

19. Sub shells present in N shell are:

 
 
 
 

20. Cathode rays has charge:

 
 
 
 

21. How many electrons can be accommodated in L-shell?

 
 
 
 

22. How many electrons can be accommodated in N-shell?

 
 
 
 

23. Which one of the following consists of three sub-shells?

 
 
 
 

24. Number of electrons that can be accommodated in f-subshell:

 
 
 
 

25. The nucleus of an atom has all of the following properties except:

 
 
 
 

26. After gaining one electron, chlorine atom attains the electronic configuration of which noble gas?

 
 
 
 

27. The value of Planck’s constant is:

 
 
 
 

28. The number of electrons that a shell can accommodate is given by formula:

 
 
 
 

29. How many electrons can be accommodated by K shell?

 
 
 
 

30. Which one of the following is the most penetrating?

 
 
 
 

31. Rutherford found in his experiment that almost all the alpha particles are:

 
 
 
 

32. The subshell that can accommodate 10 electron is:

 
 
 
 

33. How many electrons can be accommodated in M-shell:

 
 
 
 

34. The concept of orbit was used by:     

 
 
 
 

35. Which isotope is used for diagnosis of goiter?

 
 
 
 

36. Canal rays were discovered by:

 
 
 
 

37. The value of Plank’s constant is:

 
 
 
 

38. How many sub shells are there in first energy level or K shell?

 
 
 
 

39. The p subshell has:

 
 
 
 

40. Goldstein observed canal rays in:

 
 
 
 

41. According to Rutherford’s atomic theory, atom should produce:

 
 
 
 

42. If Rutherford had used neutrons instead of alpha particles, most of the neutrons would:

 
 
 
 

43. An element has 5 electrons in M-shell. Its atomic number is:

 
 
 
 

44. The p sub-shell has:

 
 
 
 

45. The nucleus of an atom is composed of:

 
 
 
 

46. Which electronic configuration is correct for nitrogen?

 
 
 
 

47. Electronic configuration of Boron is:

 
 
 
 

48. N-shell contains number of subshells:

 
 
 
 

49. Number of electrons in outermost shell of chlorine is:

 
 
 
 

50. Quantum means:       

 
 
 
 

51. Who discovered the proton?

 
 
 
 

52. Which isotope is used for treatment of cancer in the body?

 
 
 
 

53. Rutherford concluded from his experiment that most of the volume occupied by an atom is:

 
 
 
 

54. 1s₂, 2s₂, 2p₆, 3s₂, 3p₆ represents electronic configuration of:        

 
 
 
 

55. Which isotope is used to generate electricity?

 
 
 
 

56. 13C and 14C are both present in nature:

 
 
 
 

57. The name atom was derived from the Latin word ‘Atomos’ meaning:

 
 
 
 

58. Democritus was a/an __________ philosopher.

 
 
 
 

59. Number of isotopes of carbon is:

 
 
 
 

60. Deuterium is used to make:   

 
 
 
 

61. In 1897, who discovered electrons in atom?

 
 
 
 

62. Which isotope emits strongly penetrating gamma rays?   

 
 
 
 

63. Which radioisotope is used for the diagnosis of tumor in the body?

 
 
 
 

64. Rutherford’s model of the atom concentrated on the nucleus while Bohr’s model focused on the:

 
 
 
 

65. Number of isotopes of hydrogen is:

 
 
 
 

66. Quantum theory was proposed by:

 
 
 
 

67. The maximum number of electrons that can be accommodated in any shell is given by the formula:

 
 
 
 

68. Uranium has number of isotopes:

 
 
 
 

69. Which isotope is used to monitor the bone growth?

 
 
 
 

70. Who discovered cathode rays?        

 
 
 
 

71. The p sub shell can accommodate:

 
 
 
 

72. Who discovered neutron?

 
 
 
 

73. How many electrons can be accommodated in s subshell?         

 
 
 
 

74. Who proposed quantum theory?

 
 
 
 

75. Neil Bohr postulated his theory in:

 
 
 
 

76. How many times heavier mass of a proton than an electron?

 
 
 
 

77. Neil Bohr was a _______ physicist.

 
 
 
 

78. How many electrons can be accommodated in p-orbital?

 
 
 
 

79. 14C has neutron:

 
 
 
 

80. The isotope C-12 is present in abundance of:

 
 
 
 

81. Which isotope emits less penetrating beta radiation?

 
 
 
 

82. Which isotopes are used for the treatment of skin cancer?

 
 
 
 

Short Questions

A patient has goiter. How will it be detected?
An element has an atomic number 17. How many electrons are present in K, L and M shells of the atom?
As long as electron remains in an orbit, it does not emit or absorb energy. When does it emit or absorb energy?
Define isotopes.
Define nuclear fission reaction.
Describe plum pudding model. Who presented it?
Differentiate between Rutherford’s and Bohr’s atomic theories.
Differentiate between shell and sub-shell with examples of each.
Do you know any element having no neutrons in its atoms?
Explain, how anode rays are formed from the gas present in the discharge tube?
For what purpose is U⁻²³⁵ used?
Give any two differences between Rutherford’s and Bohr’s atomic theory.
Give four characteristics of cathode rays.
Give one example each of the use of radioactive isotope in medicine and radiotherapy.
Give the electronic configuration of O₂⁻ ion. 
Give the electronic configuration of oxygen and carbon.
Give two properties of positive rays.
How can you prove that angular momentum is quantized? / Calculate the value of angular momentum in 1st orbit.
How does electron differ from a neutron?
How many electrons will be in M shell of an atom having atomic number 15?
How many neutrons are present in C-12 and C-13?
How many neutrons are produced in the fission reaction of U⁻²³⁵?
How many subshells are there in second shell?
How many the maximum number of electrons that can be accommodated in a p-sub shell?
How Rutherford concluded that the size of nucleus is very small?
How was it proved that the whole mass of an atom is located at its centre?
How was it shown that atomic nuclei are positively charge?
If both K and L shells of an atom are completely filled; how many total number of electrons are present in them?
Magnesium has electronic configuration 2, 8, 2. Why does magnesium tend to lose electrons?
Name the noble gas which has the same electronic configuration as the Phosphorus 31​P15 3−ion has.
Name the particles which determine the mass of an atom.
Quote the observations made by Rutherford.
State the electronic configuration of Mg.
U⁻²³⁵ fission produces two atoms of which elements?
What are the defects of Rutherford’s atomic model?
What is a quantum?
What is atomic number of phosphorus? Write down its electronic configuration.
What is Dalton’s atomic theory?
What is maximum capacity of a shell?
What is the classical theory of radiation? How does it differ from quantum theory?
What is the contribution of Max Planks in atomic theory?
What is the electronic configuration of a hydrogen atom?
What is the nature of charge on cathode rays?
What will be the nature of charge on an atom when it loses an electron or when it gains an electron?
What are the defects of Rutherford’s atomic model?
When U⁻²³⁵ breaks up, it produces a large amount of energy. How is this energy used?
When does an electron emit or absorb energy?
Which of the isotopes of hydrogen contains greater number of neutrons?
Who discovered an electron, a proton and a neutron?
Who discovered neutrons and how?
Why do the isotopes of an element have different atomic masses?
Why does an electron first fill 2p orbital and then 3s orbital?
Write contribution of Neil Bohr in Science.
Write down the electronic configuration of Be and Ne.
Write down the electronic configuration of chloride ion.
Write down the electronic configuration of Na.
Write down the electronic configuration of sodium ‘Na’.
Write down the electronic configuration of Sulphur. Its atomic number is 16.
Write down two observations of Rutherford.
Write down two postulates of Bohr’s theory.
Write electronic configuration of Aluminium.
Write electronic configuration of Fluorine.
Write names of two isotopes used for the treatment of skin cancer.
Write the contribution of Rutherford in Science.
Write three properties of neutrons.
Write use of Co-60.

 

Long Questions

How are cathode rays produced? What are its five major characteristics?
How was it proved that electrons are fundamental particles of an atom?
Draw a labeled diagram to show the presence of protons in the discharge tube and explain how canal rays were produced.
How Rutherford discovered that atom has a nucleus located at the centre of the atom?
One of the postulates of Bohr’s atomic model is that angular momentum of a moving electron is quantized. Explain its meaning and calculate the angular momentum of third orbit (i.e. n=3)
How did Bohr prove that an atom must exist?
What do you mean by electronic configuration? What are basic requirements while writing electronic configuration of an element (atom)?
Describe the electronic configuration of Na⁺ , Mg²⁺ and Al³⁺ ions. Do they have the same number of electrons in the outermost shell?
Give the applications of isotopes in the field of radiotherapy and medicines.
What is an isotope? Describe the isotopes of hydrogen with diagrams.
Compare the differences between Rutherford’s and Bohr’s atomic theories.
Write down the postulates of Bohr’s atomic theory.
Describe the Rutherford’s atomic model. Also write its defects.
Discuss the results concluded by Rutherford.
Write the results of Rutherford’s atomic model.
State any five properties of cathode rays.
Who discovered proton? Discuss its properties.
How neutrons were discovered? Write their properties.

 

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