Solid state 1 (CBSE)

 A metal crystallizes in a body centred cubic structure. If 'a' is the edge length of its unit cell, 'r' is the radius of the sphere. What is the relationship between 'r' and 'a'?

• r = a/2√2

• r = √3/4a

• r = a/2

• r = √3/2a

 If the radius of the octahedral void is 'r' and radius of the atoms in close packing is 'R'. What is the relation between 'r' and 'R'?

• r = 41.4 R

• r = 0.3010 R

• r = 0.414 R

• r = 0.4 R

 In a close packing of N spheres, how many tetrahedral voids are there?

• N

• N/2

• 2N

• N²

What is the coordination number of atoms in a cubic close-packed structure?

• 8

• 12

• 6

• 4

 How many atoms can be assigned to its unit cell if an element forms a body-centered cubic cell?

• 1

• 2

• 3

• 4

 How many atoms can be assigned to its unit cell if an element forms a face-centered cubic cell?

• 1

• 2

• 3

• 4

Some of the very old glass objects appear slightly milky instead of being transparent. Why?

• because glass is an amorphous solid

• Due to ageing of glass

• Due to some crystallization in that region

• due to collection of some dirt inside the glass

An ionic compound AB₂ possesses CaF₂, type of crystal structure. Write the coordination numbers of A²⁺ and B^- ions in crystals of AB₂.

• C. N. of A²⁺ = 2;

  C. N. of B^-=4.

• C. N. of A²⁺ = 4;

  C. N. of B^-=8.

• C. N. of A²⁺ = 8;

  C. N. of B^-=4.

• C. N. of A²⁺ = 4;

  C. N. of B^-=4.

An iron oxide crystallizes in a hexagonal close-packed arrangement of oxide ions with two out of every three octahedral voids occupied by iron. Give the formula of the iron oxide.

• FeO

• Fe₂O₃

• Fe₃O₄

• Fe₃O₂

If three elements X, Y, and Z crystallize in a cubic solid with X atoms at the corners, Y atoms at the cube centers, and Z atoms at the faces of the cube, then write the formula of the compound.

• XYZ

• XYZ₂

• XYZ₃

• XYZ₄