Crystal Lattice and Unit Cell

Q.

Select the appropriate option.

1. Image 1 is crystal lattice, Image 2 is crystal lattice

2. Image 1 is crystal lattice, Image 2 is space lattice

3. Image 1 is space lattice, Image 2 is crystal lattice

4. Image 1 is space lattice, Image 2 is crystal lattice

Q.

In a crystal, the atoms are located at the positions where potential energy is

1. maximum

2. zero

3. minimum

4. infinite

Q. The following figure shows the unit cell of a compound, i.e., a mixed oxide of yttrium, barium and copper. The formula of mixed oxide is $Y_{a}B{a}_{b}C{u}_c{O}_d$.

Find the value of $a+b+c+d$.

Q.

How will you distinguish between the following pair of terms :

(i) hexagonal close-packing and cubic close-packing?

(ii) crystal lattice and unit cell ?

(iii) tetrahedral void and octahedral void?

Q. Why is the window glass of old building thick at the bottom ?

Q. Which of the following crystal has unit cell such that $a\ne b\ne c$ and $\alpha \ne \beta \ne \gamma \ne {90}^o?$

1. $K_{2}S{O}_4$
2. $NaN{O}_3$
3. $KN{O}_3$
4. $K_{2}C{r}_2{O}_7$

Q. In a solid $AB$ having $NaCl$ structure atoms, occupy the corners of the unit cell. If all the face centred atoms along one of the axis are removed, then the resultant stoichiometry of the solid is:

1. $A{B}_2$
2. $A_{2}B$
3. $A_4{B}_3$
4. $A_3{B}_4$

Q. A lattice is defined as

1. the amount of energy required, per mole, to separate the ions from their lattice positions to an infinte distance in the gas phase
2. the distance separating the cations and anions
3. a set of all points with identical environments within crystal
4. the arrangement of electrons in various energy levels

Q. The contribution of particle at the edge centre to a particular unit cell is :

1. $\frac{1}{2}$
2. $\frac{1}{4}$
3. $1$
4. $\frac{1}{8}$

Q. Which of the following information(s) is/are incorrect regarding the voids formed in three-dimensional HCP of identical spheres?

1. A tetrahedral void is formed when a sphere of the second layer is present above the triangular void of the first layer
2. All the triangular voids are not covered by the spheres of the second layer
3. Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular shapes of these voids do not overlap
4. Octahedral voids are formed when the triangular voids in the second layer exactly overlap with similar voids in the first layer