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
Assertion (A) The total number of atoms present in a simple cubic unit cell is one.
Reason (R) Simple cubic unit cell has atoms at its corners, each of which is shared between eight adjacent unit cells.
Assertion (A) Graphite is a good conductor of electricity however diamond belongs to the category of insulators.
Reason (R) Graphite is soft in nature on the other hand diamond is very hard and brittle.