2nd Year Chemistry Chapter 1 – Periodic Classification of Elements Notes MCQs Short Questions Solution

chemistry 12th notes chapter No 1

1. The numbers of elements classified by Newlands in the periodic table are:

 
 
 
 

2. In Potassium super oxide (KO₂) oxidation state of O is:

 
 
 
 

3. Which of the following has greatest metallic character:

 
 
 
 

4. 6th period of the periodic table contains normal elements:

 
 
 
 

5. Position of isotopes in the periodic table was explained by:

 
 
 
 

6. In the long form of the periodic table, the most electropositive elements occupy:

 
 
 
 

7. Elements after uranium are called:

 
 
 
 

8. Amphoteric oxide is formed by:

 
 
 
 

9. Mark the correct statement:

 
 
 
 

10. Mark the correct statement.

 
 
 
 

11. Hydrogen can be placed above the groups of the periodic table:

 
 
 
 

12. When hydrogen loses its electron to form Htion then it resemble:

 
 
 
 

13. Who introduced the zero group:

 
 
 
 

14. Which of the following pairs are chemically dissimilar:

 
 
 
 

15. Mark the correct statement:

 
 
 
 

16. Mark the correct statement:

 
 
 
 

17. Which of the following is not iso-electronic with others:

 
 
 
 

18. Number of elements present in the 5th period of periodic table is:

 
 
 
 

19. Which of the following iso-electronic species have largest size?

 
 
 
 

20. Among the following elements the highest value of electron affinity is shown by:

 
 
 
 

21. The melting point is lowest for:

 
 
 
 

22. Members of group IA are called:

 
 
 
 

23. Hydrogen can be placed with the element of group (IV-A) because both:

 
 
 
 

24. Mark the correct statement

 
 
 
 

25. According to Newland’s arrangement of elements recurrence (periodicity) of properties take place at every:

 
 
 
 

26. Mark the correct statement:

 
 
 
 

27. Members of group IB are called:

 
 
 
 

28. The number of elements in fourth period of periodic table is:

 
 
 
 

29. Generally metals form oxides:

 
 
 
 

30. Which of the following does not exhibit the “periodicity” in properties of the elements:

 
 
 
 

31. In the Mendeleev’s periodic law the properties of elements are periodic  function of their:

 
 
 
 

32. The element with atomic number 9 is closest in chemical properties with element of atomic-number:

 
 
 
 

33. Period six in periodic table contain which “block” elements:

 
 
 
 

34. Which of the following set has coinage in it?

 
 
 
 

35. Polymeric (Intermediate) hydride shall be formed by:

 
 
 
 

36. Which statement is correct

 
 
 
 

37. The elements of group Il-A are called.

 
 
 
 

38. Mark the correct statement

 
 
 
 

39. Which of the following in not true for metalloids:

 
 
 
 

40. Which of the following oxides is Amphoteric in character:

 
 
 
 

41. SnCl₄ is a:

 
 
 
 

42. The covalent hydrides are usually:

 
 
 
 

43. Which of the halides show bridge type structure:

 
 
 
 

44. Mark the correct statement:

 
 
 
 

45. 7th period of the periodic table contains normal elements:

 
 
 
 

46. Which of the following is metalloid?

 
 
 
 

47. The division of elements into blocks in the modern periodic table is based on:

 
 
 
 

48. In periodic table all the non-metals are placed under which of the blocks?

 
 
 
 

49. Encircle the correct statement:

 
 
 
 

50. The Ionization energy of Sodium is:

 
 
 
 

51. Which statement is incorrect:

 
 
 
 

52. Periodic table has been divided into four blocks, which blocks contain highest elements:

 
 
 
 

53. The concept of atomic number was introduced by

 
 
 
 

54. Hydrides can be classified into:

 
 
 
 

55. Total groups in modern periodic table:

 
 
 
 

56. Mork the correct statement

 
 
 
 

57. Transition elements in 4th period is

 
 
 
 

58. Mark the correct statement:

 
 
 
 

59. Select one of the following oxides which is not amphoteric in nature:

 
 
 
 

60. The force of attraction of an element on shared pair of electron is known as:

 
 
 
 

61. Mark the correct statement:

 
 
 
 

62. Among the pure ionic compounds, the ——- have the highest lattice energies:

 
 
 
 

63. Which of the following halides is polymeric?

 
 
 
 

64. The correct order of electron affinity among the following is:

 
 
 
 

65. Which of the following represents elements in order of increasing atomic radii:

 
 
 
 

66. Which of the highest melting point?

 
 
 
 

67. Non-metals usually exist as:

 
 
 
 

68. In a period, from left to right in the periodic table, the size of atom generally:

 
 
 
 

69. Mosley concluded by the X-ray studies of the elements that physical and chemical properties of elements depend upon:

 
 
 
 

70. The element with highest first ionization energy is:

 
 
 
 

71. The decrease in nuclear force on valence electrons, because of the increase in number of shells containing electrons and layering above is known as:

 
 
 
 

72. Mark the correct statement:

 
 
 
 

73. Which one of the following oxides is Amphoteric in nature:

 
 
 
 

74. Ga has oxidation state:

 
 
 
 

75. Keeping in view the size of atoms, which order is the correct one:

 
 
 
 

76. The highest acidity is shown by:

 
 
 
 

77. Which of the following sets of atoms are arranged in order of decreasing electronegativity?

 
 
 
 

78. Which of the following has highest value of Ionization Energy:

 
 
 
 

79. Which of the following set has greater ionization energy?

 
 
 
 

80. M.Pt is highest for the elements of group:

 
 
 
 

81. Elements of group II-B are called:

 
 
 
 

82. Which one is an incomplete period?

 
 
 
 

83. The number of shells in an element reflects its:

 
 
 
 

84. Which element has the largest first ionization energy:

 
 
 
 

85. Alkali metals in each period have:

 
 
 
 

86. The number of electrons in valence shell of an element reflects its:

 
 
 
 

87. Lead monoxide is:

 
 
 
 

88. Which electronic sub-shell in lanthanides is incompletely filled:

 
 
 
 

89. Mark the correct statement:

 
 
 
 

90. Which of the following elements is most electronegative:

 
 
 
 

91. Which of the following is most acidic?

 
 
 
 

92. The element will belong to the group:

 
 
 
 

93. The basis of modern periodic law is:

 
 
 
 

94. Atomic number was discovered by Mosley in:

 
 
 
 

95. Ionic hydrides react with water to form:

 
 
 
 

96. The highest ionization energy is possessed by:

 
 
 
 

97. Variable valency is shown by:

 
 
 
 

98. Mark the correct statement:

 
 
 
 

99. The oxides of metals are generally:

 
 
 
 

100. The decrease in atomic sizes is much prominent across rows containing elements of:

 
 
 
 

101. Mark the correct statement:

 
 
 
 

102. Period 5 in modem periodic table contains how many elements:

 
 
 
 

103. The 7th period of the period table contains normal elements:

 
 
 
 

104. Which one of the following is not ionic hydride:

 
 
 
 

105. Which of the following pair of atomic numbers represents IIA elements:

 
 
 
 

106. Highest Hydration energy is shown by:

 
 
 
 

107. 6th period contains the number of elements

 
 
 
 

Short Questions

1. Alkali metals give ionic hydrides. Give reason?
2. Define electron affinity. Discuss its trend in the periodic table.
3. Define Mendeleev’s and modern periodic law.
4. Describe essential features of elements of period six of Periodic Table?
5. Elements of group VI-A show the variable oxidation states except oxygen.Why?
6. Give any two resemblances of hydrogen with IVA elements.
7. Give four improvements made in Mendeleev’s periodic law
8. Give two defects in Mendeleev’s Periodic Table?
9. How covalent halides differ from ionic halides. Give examples and reasons?
10. How do you justify that the size of an ion shrinks with the increasing positive charge?
11. How do you justify the position of hydrogen at the top of alkali metals (group IA)?
12. How does hydrogen resemble with alkali metals?
13. How does hydrogen resemble with elements of group IV-A?
14. How does Moseley’s periodic law help to correct the rearrangements of some elements?
15. How does the Mendeleev’s periodic table help us to correct the atomic masses of some of the elements?
16. How does the nature of orbital influence the value of ionization energies of elements?
17. How the shielding effect is one of the important parameters to determine the size of an atom?
18. Hydration energies of ions are in the following order. Al⁺³>Mg⁺²>Na⁺¹ justify it.
19. In what respects does hydrogen differ from halogens?
20. Inspite of increasing the nuclear charge down the group atomic radii increase. Give reasons?
21. Mostly it is observed that the elements of group VIII-A have zero oxidation number,Why?
22. Name various classes of hydrides.
23. Oxidation states usually remain same in a group. Why?
24. The first electron affinity of oxygen is negative but the second is positive.Why?
25. The hydration energies of the ions are in the following order. Give reason: AI³⁺>Mg²⁺>Na⁺¹?
26. The ionization energy is measured by taking the atom in the isolated state?
27. The melting and boiling points of the elements increase from left to the right upto the middle of s-and p-block elements and decrease on wards.Why?
28. The oxidation states vary in a period but remain almost constant in a group.Why?
29. What are amphoteric oxides? Give an example.
30. What are hydrides? What is the trend of boiling points of hydrides of group VI down the group?
31. What are s-block elements and why are they called so?
32. What happens when acidic and basic oxides combine with each other?
33. What is Lanthanide contraction?
34. Which is the first d-block series and what is the name of the coinage metals in it?
35. Why alkali metals give ionic hydrides?
36. Why d and f-block elements are called transition elements?
37. Why diamond is a non-conductor and graphite fairly a good conductor of electricity?
38. Why do ionization energies decrease down the group and increase left to right?
39. Why do metals conduct electricity?
40. Why graphite is a good conductor of electricity but diamond is not?
41. Why hydrogen can be placed over group IVA of the periodic table
42. Why is it true that the higher oxidation state of an element gives greater % of covalent character?
43. Why is the metallic character increase down the group of s-block elements?
44. Why melting and boiling points of elements belonging to groups VA to VIIA are lower? Discuss the trend of ionization energy in the periodic table.
45. Why metallic character increases from top to bottom in a group of metal?
46. Why most of the elements release energies when electrons are added in their outermost orbitals?
47. Why PbCl₂ is ionic but PbCl₄ is fairly covalent compound?
48. Why the addition of electron in the outermost orbitals is studied by taking the atoms in the isolated state?
49. Why the atomic radii decrease from left to the right and increase from top to the bottom in periodic table?
50. Why the electrical conductivities of the elements are related with the free electrons?
51. Why the electron affinities of elements of group II-A are less than those of group I-A?
52. Why the elements of group III-A have less ionization energy value than II-A?
53. Why the elements of group III-A to group VII-A are called P-block elements?
54. Why the elements of group VI-A have less ionization energy values than V-A?
55. Why the elements of groups I-A and II-A are good metals of the Periodic Table?
56. Why the elements of I-A II-A and III-A have electrical conductivities?
57. Why the elements on top right of the Periodic Table are non-metallic in nature?
58. Why the hydration energies of halide ions decrease from F- to I-?
59. Why the hydration energy depends upon the size of the ion?
60. Why the ionic halides are mostly given by the elements of group I-A and II-A and go on decreasing from left to right?
61. Why the ionic radius of a negative ion is greater than its atomic radius?
62. Why the ionic radius of a positive ion is smaller than its neutral atom?
63. Why the ionization energies decrease down the groups?
64. Why the ionization energies increase from left to the right in a period?
65. Why the melting and boiling points of halogens increase from top to the bottom?
66. Why the melting points of halides decrease from left to the right in a period?
67. Why the oxidation states of noble gases are usually zero?
68. Why the second value of electron affinity of all the element is positive?
69. Write name and symbol of an element from s block that has zero oxidation state. Also write its electronic configuration.
70. Zn, Cd, Hg were placed along with alkaline earth metals in Mendeleev’s periodic table. How this confusion was removed in Modern periodic table?

Long Questions

1. Discuss various periods in the modern periodic table.
2. How the classification of elements in different- blocks helps in understanding their chemistry?
3. What is meant by Period.
4. How elements in the Periodic table are classified into blocks?
5. Describe different periods of the periodic table
6. Explain main features of the modern periodic table.
7. Discuss the position of hydrogen over 7th -A group.
8. Discuss the position of hydrogen over Alkali Metals.
9. Discuss the position of hydrogen over VII A-Group elements.
10. Discuss the position of hydrogen in Group IV-A of periodic table.
11. How hydrogen resembles with group I A elements and differs from IV A elements?
12. Discuss the position of Hydrogen in group 1st and VIl (A) of periodic table.
13. Define Ionization Energy. How it varies within a group and across a period?
14. Give the periodic trend of ionization energy and electron affinity.
15. Explain variation of (i) ionization potential and (h) electrical conduction along period and group.
“16. Explain periodic trends in the following physical properties
(i) Atomic radius (ii) Electron affinity .”
17. Define Ionization eneran? How does it differ along the period and down the group?
18. Why diamond is non-conductor and graphite is fairly a good conductor?
19. Define Hydration Energy. Give example. Explain its trend in the Periodic Tabie.
20. Describe trend of metallic character in groups and periods and discuss the impact of atomic size on it
21. Define Halides. Give their classification.
22. Define hydrides. Give their classification and properties.
23. Write a brief note on halides.
24. What are halides? Classify them on the basis of nature of bonding. Describe covalent halides in detail.
25. What are oxides? Classify them on the basis of acidic and basics nature with examples
26. Define oxides. How are they classified? Give example of each class.
27. What are halides? Classify them on the basis of nature of bonding. Describe only ionic halides in detail.
28. Explain main features of Modern Periodic Table.
29. Give the periodic trends of energy and electron affinity

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