Match the defects given in Column I with the statements in given Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Simple vacancy defect | 1. | Shown by non-ionic solids and increases density of the solid |
| B. | Simple interstitial defect | 2. | Shown by ionic solids and decreases density of the solid |
| C. | Frenkel defect | 3. | Shown by non-ionic solids and density of the solid decreases |
| D. | Schottky defect | 4. | Shown by ionic solids and density of the solid remains the same |
A. $\rightarrow$ (3) B. $\rightarrow$ (1) C. $\rightarrow$ (4) D. $\rightarrow$ (2)
A. When some of lattice sites are vacant in any non-ionic solid, the crystal is said to have vacancy defect and due to decrease in number of particles present in crystal lattice the density of crystal decreases.
B. Simple interstitial defect are shown by non-ionic solids in which constituent particles is displaced from its normal site to an interstitial site. Hence, density of solid increases.
C. Frenkel defect is shown by ionic solids in which smaller ions get dislocated from its normal site to its interstitial site which lead to decrease its density.
D. Schottky defect is shown by ionic solids in which equal number of cation and anion get missed from ionic solids and thus, density of solid decreases.
Match the type of unit cell given in Column I with the features given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Primitive cubic unit cell | 1. | Each of three perpendicular edges compulsorily have the different edge length i.e., $a\ne b \ne c$ |
| B. | Body centred cubic unit cell | 2. | Number of atoms per unit cell is one |
| C. | Face centred cubic unit cell | 3. | Each of the three perpendicular edges compulsorily have the same edge length i.e., $a=b=c$ |
| D. | End centred orthorhombic unit cell | 4. | In addition to the contribution from the corner atoms the number of atoms present in a unit cell is one |
| 5. | In addition to the contribution from the corner atoms the number of atoms present in a unit cell is three |
A. $\rightarrow(2,3)$ B. $\rightarrow(3,4)$ C. $\rightarrow(3,5)$ D. $\rightarrow(1,4)$
A. For primitive unit cell, $a=b=c$
Total number of atoms per unit cell $=1 / 8 \times 8=1$
Here, $1 / 8$ is due to contribution of each atom present at corner.
B. For body centred cubic unit cell, $a=b=c$
This lattice contain atoms at corner as well as body centre. Contribution due to atoms at corner $=1 / 8 \times 8=1$ contribution due to atoms at body centre $=8$
C. For face centred unit cell, $a=b=c$
Total constituent ions per unit cell present at corners $=\frac{1}{8} \times 8=1$
Total constituent ions per unit cell present at face centre $=\frac{1}{2} \times 6=3$
D. For end centered orthorhombic unit cell, $a \neq b \neq c$
Total contribution of atoms present at corner $=\frac{1}{8} \times 8=1$
Total contribution of atoms present at end centre $=\frac{1}{2} \times 2=1$
Hence, other than corner it contain total one atom per unit cell.
Match the types of defect given in Column I with the statement given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Impurity defect | 1. | NaCl with anionic sites called F-centres |
| B. | Metal excess defect | 2. | FeO with Fe$^{3+}$ |
| C. | Metal deficiency defect | 3. | NaCl with Sr$^{2+}$ and some cationic sites vacant |
A. $\rightarrow(3)$ B. $\rightarrow$ (1) C. $\rightarrow$ (2)
A. Impurity defect arises due to replacement of one common ion present in any crystal by another uncommon ion.
B. Metal excess defect is due to missing of cation from ideal ionic solid which lead to create a F-centre generally occupied by unpaired electrons. e.g., NaCl with anionic site.
C. Metal deficiency defect in $\mathrm{FeO}, \mathrm{Fe}^{3+}$ exists along with $\mathrm{Fe}^{2+}$ which lead to decrease in metal ion(s) so this is a type of metal deficiency defect.
Match the items given in Column I with the items given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Mg in solid state | 1. | p-type semiconductor |
| B. | MgCl$_2$ in molten state | 2. | n-type semiconductor |
| C. | Silicon with phosphorus | 3. | Electrolytic conductors |
| D. | Germanium with boron | 4. | Electronic conductors |
A. $\rightarrow$ (4) B. $\rightarrow$ (3) C. $\rightarrow$ (2) D. $\rightarrow(1)$
A. Mg in solid state show electronic conductivity due to presence of free electrons hence, they are known as electronic conductors.
B. $\mathrm{MgCl}_2$ in molten state show electrolytic conductivity due to presence of electrolytes in molten state.
C. Silicon doped with phosphorus contain one extra electron due to which it shows conductivity under the influence of electric field and known as p-type semiconductor.
D. Germanium doped with boron contain one hole due to which it shows conductivity under the influence of electric field and known as $n$-type semiconductor.
Match the type of packing given in Column I with the items given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Square close packing in two dimensions | 1. | Triangular voids |
| B. | Hexagonal close packing in two dimensions | 2. | Pattern of spheres is repeated in every fourth layer |
| C. | Hexagonal close packing in three dimensions | 3. | Coordination number = 4 |
| D. | Cubic close packing in three dimensions | 4. | Pattern of sphere is repeated in alternate layers |
A. $\rightarrow(3)$ B. $\rightarrow$ (1) C. $\rightarrow$ (4) D. $\rightarrow$ (2)
A. Square close packing in two dimensions each sphere have coordination number 4, as shown below
B. Hexagonal close packing in two dimensions each sphere have coordination number 6 as shown below and creates a triangular void
C. Hexagonal close packing in 3 dimensions is a repeated pattern of sphere in alternate layers also known as $A B A B$ pattern
D. Cubic close packing in a 3 dimensions is a repeating pattern of sphere in every fourth layer
