CHAPTER 3 Atomic Structure –

1. Which of the following is a fundamental particle of an atom?

2. Consider the following statements:

1. Atoms of elements are made up of three fundamental particles – electron, proton, and neutron.

2. Hydrogen is an exception, whose atom has only two particles – electron and proton.

Which statement is correct?

3. The first fundamental particle of the atom to be discovered was:

4. Who discovered the existence of electron or found electron?

5. Which of the following is NOT correct regarding electron?

6. How was the charge of an electron determined?

7. The charge on an electron is:

8. Which of the following statements is true about cathode rays?

9. Consider the following statements:

1. Cathode rays are made of electrons.

2. Anode or canal rays are made of protons.

Which statement is correct?

10. Which of the following fundamental particles has the least mass?

11. “Atom is a positively charged sphere in which electrons are embedded.” Who gave this idea regarding the atom?

12. Who developed the atomic structure model?

13. When Rutherford bombarded a thin metal foil with alpha particles for discovering the nucleus, then—

14. Who presented the planetary model of the atom?

15. In Rutherford's experiment to determine atomic structure, why was a thin foil used instead of a thick sheet?

16. Who discovered the nucleus of an atom?

17. In Rutherford’s discovery of the nucleus, which particles were used?

18. Which of the following is a negatively charged or neutral particle?

19. The charge on a proton is equal to the charge on—

20. The mass of a neutron is approximately equal to the mass of—

21. Which of the following pairs is NOT correct?

22. Consider the following statements:

1. Atomic number is the number of protons.

2. Atomic number is the number of neutrons.
   Which statement(s) is/are correct?
   

23. Regarding atomic number, which one is NOT correct?

24. The smallest particle of an element is—

25. Nuclear fission reaction is—

26. In nature, free neutrons are NOT found in—

27. Which of the following is NOT a charged particle?

28. The energy of a shell—

29. Which of the following is correct?

30. In an atom, which shell has the lowest energy?

31. The maximum number of electrons in a shell is given by which formula?

32. Consider the following statements:

1. The paths in which electrons revolve around the nucleus are called orbits by Rutherford.

2. The paths in which electrons revolve, according to Niels Bohr, are called shells.
   Which statement(s) is/are correct?

33. The maximum number of electrons present in an atom depends on—

34. Consider the following:

1. The maximum number of electrons in the M shell will be 18.

2. If the third shell is the outermost shell, it can only hold 8 electrons.
   Which statement(s) is/are correct?
   

35. The correct order of shell energies is—

36. Which shell can have a maximum of 32 electrons?

37. Which particle keeps electrons in their orbits around the nucleus?

38. Who discovered neutrons?

39. Which information is NOT obtained from Rutherford's model?

40. In the following, the charge on an electron is equal and opposite to—

41. The number of protons in the nucleus of an element is equal to—

42. Atomic number is related to—

43. What is the mass number?

44. If an element has atomic number Z and mass number A, then the number of neutrons is—

45. Which of the following is NOT correct regarding atomic number?

46. An element has mass number 23 and its nucleus contains 12 neutrons. What will be the atomic number of the element?

47. An atom has 8 electrons and 8 protons. What will be the atomic number of the atom?

48. How many protons are there in the element ?

49. An element with atomic number Z and mass number A has how many electrons?

50. Consider the following statements:

1. Atomic mass number is the sum of the number of protons and neutrons in the nucleus.

2. Atomic number is always less than or equal to the atomic mass number.
   Which statement(s) is/are correct?
   

51. An atom has 8 electrons and 8 protons. What will be the number of neutrons in it?

52. In , what are the numbers of protons and electrons?

53. In, what are the numbers of protons and neutrons?

54. How many electrons are there in?

55. An element has atomic mass 23 and atomic number 11. How many neutrons does it have?

56. An atom has 9 electrons, 9 protons and 10 neutrons. What will be its mass number?

57. An element has 2 protons, 2 neutrons and 2 electrons. What will be its mass number?

58. An element has 19 protons and 20 neutrons. What will be its mass number?

59. How many neutrons are there in

61. Consider the following statements:

1. The mass number is almost twice the atomic number.

2. The mass number is almost equal to the atomic number.
   Which statement(s) is/are correct?
   

62. An element has atomic mass 4 amu and its nucleus contains 2 protons. How many neutrons will it have?

64. Who discovered the neutron?

63. Which neutral particle has no mass number and no charge?

65. Which statement is incorrect regarding atomic mass?

66. Nuclear number and atomic number -

What is the relationship?

67. The difference between the mass number and the atomic number is called -

68.Which one of the following is not correct?

69. What is the nucleus of a hydrogen atom called?

70. Which of the following is the most fundamental characteristic of an element?

71. The nature of elements can be determined by?

72. The chemical nature of an element depends on –

73. The chemical properties of an element depend on?

74. The chemical behavior of an atom depends on its –

75. Two atoms are called isotopes when –

76. In the atoms of isotopes, which number is not the same?

77. The difference between the isotopes of an element is due to the presence of a different number of –

78.Two isotopes of an element differ in which properties?

79. An isotope nucleus is a nucleus in which –

80. In isotopes –

1. They have the same chemical properties.

2. They have different physical properties.

3. They have the same physical properties but different chemical properties.

81. Consider the following statements:

1. In the nucleus of an isotopic atom, the number of protons is the same.

2. In the nucleus of isobaric atoms, the number of protons is different.

Which of the above statements is/are correct?

82. Atoms of different elements that have the same mass number but different atomic numbers are called –

85. How many isotopes of hydrogen are there?

86. Which element has the largest number of isotopes?

"87. How many isotopes does polonium have?

88. Elements having the same atomic number but different atomic masses are:

"89. Atoms of different elements that have the same number of neutrons are called —

"90. Isotones are those in which —

"91. Which of the following are isoneutronic?"

92. Isotones have —

93. Which of the following statements is incorrect?

94. Nuclei that have the same number of neutrons but a different number of protons are called —

"95. ₁₅P³¹ and ₁₄Si³⁰ are examples of —

"96. Consider the following statements:

1. In the nuclei of isobaric elements, the number of protons is different.

2. In the nuclei of isobaric elements, the sum of the numbers of protons and neutrons is the same.

Which of the above statements is/are correct?

"97. Cobalt isotope (Co-60) is used for —

98. Which isotope is used in dating to determine the age of rocks?

99. Which isotope is used to determine the age of fossils?

"100. Which radioisotope is used to control blood cancer (leukemia)?

"101. Cobalt-60 is commonly used in radiation therapy for diseases like cancer because it emits —

"102. Which isotope is used to detect the condition of blood clots in the circulatory system?

103. Which isotope is used in the treatment of goiter?

104. Which isotope is used to detect tumors?

"105. Ions that have the same number of electrons are called —

106. Al³⁺ is isoelectronic with —

"107. Which of the following pairs are isoelectronic ions?

108. Isotopes of an element have —

109. Which of the following is not a nucleon?

"110. The quantum number that indicates the average distance of the electron orbit from the nucleus and the average energy of the electron is —

"111. The quantum number that measures the energy produced due to the angular momentum of an electron revolving in an orbit is —

"112. The quantum number that specifies the orientation of an orbital in space is —

"113. Which quantum number is required to explain the Zeeman effect?

"114. In the context of a chemical element’s atom, the magnetic quantum number is related to —

"115. Consider the following statements —

1. The principal quantum number indicates the energy and size of the shells.

2. The azimuthal quantum number indicates the shape of the subshells.

3. The magnetic quantum number indicates the orientation of the subshells.

Which of the above statements is/are correct?

116. Which subshell cannot be present in the M shell of an atom?

"117. What is the shape of the s-orbital?

"118. Consider the following statements —

1. The K-shell has the minimum energy.

2. The f-subshell has the maximum energy.

Which of the above statements is/are correct?

"119. Which of the following options is not correctly matched?
Subshell — Maximum number of electrons

120. How many orbitals are there in a p-subshell?

"121. The azimuthal quantum number determines —

"122. In an atom, no two electrons can have all four quantum numbers the same. This rule is associated with which scientist?

123. पॉली के अपवर्जन सिद्धान्त से निम्न में कौन-से निष्कर्ष
प्राप्त होते है ?
(a) किसी कक्षा में इलेक्ट्रॉन की अधिकतम संख्या 2
होती है।
(b) किसी कक्षा में सबशेलो की संख्या कक्षा की मुख्य
कवांटम संख्या के बराबर होती है।
(c) एक आर्बिटल में अधिक से अधिक दो इलेक्ट्रॉन रह
सकते है और उन दोनों के चक्रण की दिशाएँ एक-दूसरे
के विपरित होगी।
(d) इनमें से सभी

"124. 'Electrons do not pair up until all available empty orbitals of the same energy are singly occupied.' This principle is called —

"125. Which scientist improved Bohr’s theory by proposing elliptical orbits for the path of the electron?

126. The principal quantum number is related to —

"127. 'It is not possible to determine both the position and velocity of small particles like electrons simultaneously' — this statement is of —

"128. The sequential filling of electrons in subshells occurs according to which principle/rule?

"129. Consider the following statements —

1. The subshell with the lower value of (n + ℓ) is filled with electrons first.

2. When two subshells have the same value of (n + ℓ), electrons enter the subshell with the lower value of n first.

Which of the above is/are in accordance with the Aufbau principle?

"130. The electronic configuration of an atom or ion can be defined by —

"131. Which of the following electronic configurations is not possible?

The correct electronic configuration of Pd (Palladium, atomic number 46) is –

133.The electronic configurations 1s² 2s² 2p⁶ belong to –

134. The electronic configuration of K (atomic number – 19) is –

135. Which of the following is the electronic configuration of the sodium ion?

136. Which of the following is the electronic configuration of the chloride ion (Cl⁻)?

138. The electronic configuration of an atom with atomic number 20 is –

139. For which of the following elements is the electronic configuration not according to the Aufbau principle?

140. The size of a nucleus is

141. The number of core electrons in a sodium atom is –

142. The number of valence electrons in aluminum is –

144. An electron will first fill

145. The configuration 1s² 2s² 2p⁶ 3s¹ can be represented in which of the following forms? 

146. How many valence electrons will be present in Cl⁻ (chloride ion)?

147. Which of the following elements has the electronic configuration 2, 8, 4?

148. M²⁺ has the electronic configuration 2, 8, 14 and atomic mass 56. How many neutrons are present in its nucleus?

149. Consider the following statements:

1. Sodium, Aluminium, Phosphorus, and Chlorine have the same number of core electrons.

2. Sodium, Aluminium, Phosphorus, and Chlorine have the same number of valence electrons.

Which of the above statements is/are correct?

150. An atom has the electronic configuration 2, 8, 2. How many valence electrons does it have?