76. Based on the cohesive energy of an ionic solid, which of the following is not a property of the ionic solid?

1. 1. It forms relatively stable and hard crystals

   
   
   

   2. It is a poor electric conductor

   
   
   

   3. It has a high vaporization temperature

   
   
   

   4. None of the above

   
   
   

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   NA

   Correct Option: D

   NA

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77. The coordination number for structure of gold is:

1. 1. 4

   
   
   

   2. 16

   
   
   

   3. 12

   
   
   

   4. 1

   
   
   

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   The coordination number for structure of gold is 12.

   Correct Option: C

   The coordination number for structure of gold is 12.

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78. The number of effective atoms per unit cell in a FCC structure is:

1. 1. one

   
   
   

   2. four

   
   
   

   3. six

   
   
   

   4. two

   
   
   

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   NA

   Correct Option: B

   NA

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79. In a simple cubic structure, are the direction [100] and plane (100) parallel?

1. 1. No

   
   
   

   2. Yes

   
   
   

   3. May be both

   
   
   

   4. Can’t be predicted

   
   
   

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   NA

   Correct Option: A

   NA

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80. A unit cell is:

1. 1. the smallest group of atoms when regularly repeated, forms a crystal

   
   
   

   2. the basic building block of a crystal

   
   
   

   3. a cube containing the largest number of atoms

   
   
   

   4. an agglomerated structure

   
   
   

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1. View Hint View Answer Discuss in Forum

   A unit cell is the smallest group of atoms when regularly repeated, forms a crystal.

   Correct Option: A

   A unit cell is the smallest group of atoms when regularly repeated, forms a crystal.

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