II. Match the following.
Group – A Group – B
71. Alkali metal family ( ) A) 13 (III A) group
72. Boron family ( ) B) 14 (IV A) group
73. Halogen family ( ) C) 15 (V A) group
74. Carbon family ( ) D) 17 (VII A) group
75. Nitrogen family ( ) E) 1 (I A) group
Group – A Group – B
76. Law of triads ( ) A) Newlands
77. Periodic law – at. wt. ( ) B) Moseley
78. Periodic law – at. no. ( ) C) Electronic configuration
79. Modern periodic law ( ) D) Dobereiner
80. Law of octaves ( ) E) Mendeleev
Fill in the blanks:
81. Lithium, ………. and Potassium constitute a Dobereiner’s triad.
82. ……….. was the basis of the classifications proposed by Dobereiner, Newlands and Mendeleev.
83. Noble gases belongs to ……… group of periodic table.
84. The incomplete period of the periodic table is ………..
85. The element at the bottom of a group would be expected to show ………. metallic character than the element at the top.
86. ……… proposed the law of octaves.
87. Newlands periodic table was restricted to only ………….
88. Mendeleev’s periodic law states that the physical and chemical properties of the elements are a periodic function of their ……….
89. There are ……….. vertical columns in Mendeleev’s periodic table called ………..
90. Sub group I A elements are called ……….
91. The horizontal rows in Mendeleev’s periodic table are called ……….
92. Eka-boron is later discovered as ………
93. Eka-aluminium is later identified as ………
94. Eka-silicon is discovered as ……….
95. The melting point of Gallium is ………
96. Atomic weight = Equivalent weight × ………..
97. 101th element was named as ……….
98. ………… realised that the atomic number is more fundamental characteristic of an element than its atomic weight.
99. Modern periodic law states ‘the physical and chemical properties of elements are periodic function of the …….. of their atoms’.
100. Group of elements is also called ……….
Answers:
71-E; 72-A; 73-D; 74-B; 75-C
76-D; 77-E; 78-B; 79-C; 80-A
81) sodium 82) Atomic weight
83) ‘O’ group (18th group) 84) 7th period
85) High 86) Newlands
87) 56 elements 88) atomic weight
89) eight, groups 90) alkali metals
91) periods 92) scandium
93) gallium 94) germanium
95) 32°C 96) valency
97) Mendelevium 98) Moseley
99) electronic configuration 100) element family (or) chemical family