Voids Radius Ratio Coordination Number

If NaCl is doped with 10^-4mol% of SrCl₂, the concentration of cation vacancies will be (N_A= 6.02\times 10²³mol^-1):

1. $6.02\backslash times{10}^{15}$ $mo{l}^{-1}$

2. $6.02\backslash times{10}^{16}$ $mo{l}^{-1}$

3. $6.02\backslash times{10}^{17}$ $mo{l}^{-1}$

4. $6.02\backslash times{10}^{14}$ $mo{l}^{-1}$

If 'a’ stands for the edge length of the cubic systems: simple cubic, body-centered cubic, and face-centered cubic, then the ratio of radii of the spheres in these systems will be respectively:

1. $\frac{1}{2}\mathrm{a\; :}$ $\frac{\sqrt{3}}{4}\mathrm{a}$ $:$ $\frac{1}{{\displaystyle 2}\sqrt{2}}\mathrm{a}$

2. $\frac{1}{2}\mathrm{a\; :}$ $\sqrt{3}\mathrm{a}$ $:$ $\frac{1}{\sqrt{2}}\mathrm{a}$

3. $\frac{1}{2}\mathrm{a\; :}$ $\frac{\sqrt{3}}{2}\mathrm{a}$ $:$ $\frac{\sqrt{2}}{{\displaystyle 2}}\mathrm{a}$

4. $1\mathrm{a\; :}$ $\sqrt{3}\mathrm{a}$ $:$ $\sqrt{2}\mathrm{a}$

Copper crystallizes in a face-centered cubic lattice with a unit cell length of 361 pm. The radius of the copper atom is:

1. 128 pm

2. 157 pm

3. 181 pm

4. 108 pm

The number of octahedral void(s) per atom present in a cubic close-packed structure is:

1. 1

2. 3

3. 2

4. 4

The vacant space in the BCC lattice cell is:

1. 26%

2. 48%

3. 23%

4. 32%

In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion (Ca²⁺) and fluoride ion (F^-) are:

1. 4 and 2

2. 6 and 6

3. 8 and 4

4. 4 and 8

A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75 % of octahedral voids. The formula of the compound is:

1. ${\mathrm{C}}_3{\mathrm{A}}_4$

2. ${\mathrm{C}}_2{\mathrm{A}}_3$

3. ${\mathrm{C}}_3{\mathrm{A}}_2$

4. ${\mathrm{C}}_4{\mathrm{A}}_3$

The number of tetrahedral and octahedral voids in hexagonal primitive unit cell are respectively:

1. 2, 1

2. 12, 6

3. 8, 4

4. 6, 12

What fraction of one edge centred octahedral void lies in one unit cell of fcc?

1.		2.
3.		4.