The pair having only molecular solids among the following is -

1. Brass and SiC

2. Ammonium phosphate (NH₄)₃PO₄

3. SiC and plastic 

4. Tetra phosphorus decaoxide (P₄O₁₀) and I₂

In a cubic close-packed structure, the coordination number of atoms is -

1. 12

2. 8

3. 1

4. 4

The relation between the atomic mass of unknown metal with density and the dimension of its unit cell is given by  :

(Given: All the cell edge lengths are equal)

1. \(m \ = \ \frac{\rho a^{3}N_{A}}{Z} \)
2. \(m \ = \ \rho a^{3}N_{A}Z\)
3. \(m \ = \ \frac{Z}{\rho a^{3}N_{A}}\)
4. \(m \ = \ \frac{ZN_{A}}{a^{3}\rho}\)

Select the correct option based on statements below:

The number of lattice points in one unit cell of face-centred tetragonal lattice is  -

1. 4 

2. 12

3. 14 

4. 9

The similarity between metallic and ionic crystals is -

The packing efficiency of the face-centered cubic unit cell is:
(assuming that the atoms are touching each other)

1. 52.40 %

2. 68.04 %

3. 74 %

4. 79.06 %

Silver crystallizes in fcc lattice. If the edge length of the cell is 4.07 × 10⁻⁸ cm and density is 10.5 g cm⁻³, the atomic mass of silver is -

1. 120.31 g ${\mathrm{mol}}^{-1}$

2. 107.9 g ${\mathrm{mol}}^{-1}$

3. 207.60 g ${\mathrm{mol}}^{-1}$

4. 138.52 g ${\mathrm{mol}}^{-1}$

A cubic solid is made of two elements P and Q. Atoms of Q occupy the corners of the cube and P occupy the body centre. The formula of this compound and the coordination number of Q are respectively - 

1. PQ, 8

2. P₂Q, 8

3. P₂Q₂, 8

4. PQ, 12

Niobium crystallizes in body-centred cubic structure. If the density is 8.55 g cm⁻³, the atomic radius of niobium (atomic mass 93 u) is -

1. 13.32 nm

2. 12.32 nm

3. 14.32 nm

4. 15.32 nm