Answer: Option B. -> ZnS
:
B
InZnSstructure, sulphide ions occupy allFCClattice points while $Z{n}^{2+}$ions are present in alternate tetrahedral voids.

Answer: Option D. -> 12 part
:
D
In fcc, an atom at the center is shared by two unit cells.
So, it contributes $\frac{1}{2}$to each of them.

Answer: Option B. -> Ferromagnetic
:
B
In solid state, the metal ions of ferromagnetic substances are grouped together into small regions calleddomains. Thus, each domain acts as a tiny magnet. In an unmagnetised piece of a ferromagnetic substance the domains are randomly oriented and their magnetic moments get cancelled. When the substance is placed in a magnetic field all the domains get oriented in the direction of the magnetic field and a strong magnetic effect is produced. This ordering of domains persist even when the magnetic field is removed and the ferromagnetic substance becomes a permanent magnet.

Answer: Option D. -> 26%
:
D
In face-centered cubic arrangement, 74% of the crystal space is filled

• Vacant space = 100 – 74 = 26%

Answer: Option C. -> r=√34a 
:
C
In $△EFD$,
b = a + a = 2a
Now in $△AFD$
$c^2=a^2+b^2=a^2+2a^2=3a^2$
$\to c=\sqrt{3a}$
The length of the body diagonal 'c' is equal to 4r, where r is the radius of the sphere (atom), as the three spheres along the diagonal touch each other.
Therefore, $\sqrt{3a}=4r$
$a=\frac{4r}{\sqrt{3}}$
$\to r=\frac{\sqrt{3}}{4}a$

Answer: Option B. -> Schottky
:
B
Due to presence of vacant lattice sites in Schottky defect, there is a decrease in the density of crystal.

Answer: Option B. -> A,C
:
B
Amorphous solids consist of particles of irregular shape, so it displays short range order.
Amorphous solids soften over a range of temperature, and hence doesn’t show sharp melting point.
The value of a physical property will be same from any directions in case of amorphous solids. So, they are said to be isotropic in nature.
Amorphous solids do not have a definite heat of fusion.

Answer: Option D. -> 2 and 4
:
D
The bcc cell consistes of 8 atoms at the corners and one atom at centre.
$\therefore n=(8\times \frac{1}{8})+1=2$.
The fcc cell consists of 8 atoms at the eight corners and one atom at each of the six faces.This atom at the faces is shared by two unit cells.
$\therefore n=8\times \frac{1}{8}+(6\times \frac{1}{2})=4$

Answer: Option C. -> Molybdenum (atomic mass = 95 g/mol)
:
C
The number of Argo atoms per unit cell(z) = 4
Density (d) = $10g/c{m}^3$
Edge length of unit cell (a) = 4000 nm = $4\times {10}^{-8}$cm
We know that, $d=\frac{z\times M}{a^3\times N_A}=>M=\frac{d\times a^3\times N_A}{z}=\frac{10\times (4\times {10}^{-8}{)}^3\times 6.023\times {10}^{23}}{4}=96.368$ g/mol
This value is closest to the atomic mass of molybdenum.

Answer: Option B. -> In between 0.73 and 0.41
:
B
The structural arrangement of co-ordination number ‘6’ is octahedral and its radius ratio is 0.414 - 0.732.