Introduction Crystal System

CsBr crystallises in a body-centered cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 amu and that of Br = 80 amu and the Avogadro number being 6.02\times 10²³ mol^-1, the density of CsBr is:

1. 42.5 $g/c{m}^3$

2. 0.425 $g/c{m}^3$

3. 8.25 $g/c{m}^3$

4. 4.25 $g/c{m}^3$

For a cubic crystal structure, which one of the following relations indicating the cell characteristic is correct?

1. $a\backslash neqb\backslash neqc$ $and$ $\mathrm{\backslash alpha}\backslash neq\mathrm{\backslash beta}$ $and$ $\mathrm{\backslash gamma}\backslash neq90°$

2. $a\backslash neqb\backslash neqc$ $and$ $\mathrm{\backslash alpha}=\mathrm{\backslash beta}$ $=$ $\mathrm{\backslash gamma}=90°$

3. $a=b=c$ $and$ $\mathrm{\backslash alpha}\backslash neq\mathrm{\backslash beta}$ $=$ $\mathrm{\backslash gamma}=90°$

4. $a=b=c$ $and$ $\mathrm{\backslash alpha}=\mathrm{\backslash beta}=$ $\mathrm{\backslash gamma}=90°$

Lithium metal crystallizes in a body-centered cubic crystal. If the length of the side of the unit cell of lithium is 351 pm, the atomic radius of the lithium will be:

1. 240.8 pm

2. 151.8 pm

3. 75.5 pm

4. 300.5 pm

The number of carbon atoms per unit cell of a diamond is:

1. 8

2. 6

3. 1

4. 4

The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is :

1. 2

2. 3

3. 7

4. 5