Pandey Tutorials
Sub: Chemistry Weekly Test
Time: 1.20Hrs Date: 11/05/2025
Section-A
Q.1 Multiple choice Question. ( 5 mark )
I. If the number of atom per unit in a crystal is 2, the structure of crystal
is_________________.
a) Octahedral b) Body centred cubic. c) Face centred cubic. d) Simple
cubic
II. The space occupied by the BCC unit cell arrangement is approximately
a) 50% b) 68% c) 74% d) 56%
III. Silicon is a
a) Conductor b) Semiconductor c) Non-conductor d) Metal complex
IV. Among solids the highest melting point is established by
a) Covalent solid b) Ionic solid c) Pseudo solids d) Molecular solid
V. Which defect causes decrease in the density of crystal?
a) Frenkel b) Schottky c) interstitial d) F-centre
Q.2 Very short answer. ( 5 mark )
1. What is the relationship between the radius of an atom and the edge length of a face-
centered cubic (fcc) unit cell?
2. Define polymorphism in solids.
3. Define polymorphism in solids.
4. What is a unit cell?
5. What are the intermolecular forces in molecular crystals?
Section-B
( Attempt any five ) ( 10 mark )
Q.3 Explain with diagram, the vacancy defect.
Q.4 Distinguish between crystalline solids and amorphous solids.
Q.5 What is the effect on the density of a substance in the case of a Frenkel defect?
Q.6 write the consequences of schottky defect.
Q.7 Differentiate between ionic solids and covalent solids.
Q.8 Define packing efficiency. What is its value in a simple cubiDescribe the types of point
defects in ionic solids. c lattice?
Q.9 What are anisotropic properties? Explain with respect to crystalline solids.
Q.10 State the relation between edge length (a) and radius (r) of atoms in FCC structure.
Section-C
( Attempt any four ) ( 12mark )
Q.11 Calculate the packing efficiency in a body-centered cubic (BCC) unit cell.
Q.12 State and explain the types of cubic unit cells. How many atoms are present in each?
Q.13 Define isotropy and anisotropy. Why are crystalline solids anisotropic in nature?
Q.14 Define isotropy and anisotropy. Why are crystalline solids anisotropic in nature?
Q.15 Silver crystallizes in a face-centered cubic (FCC) structure. If the edge length of the
unit cell is 400 pm, calculate the density of silver. (Atomic mass of Ag = 108 g/mol)
Q.16 Describe the types of point defects in ionic solids.
Section-D
( Attempt any three ) ( 12 mark )
Q.17 Explain the different types of cubic unit cells (Simple Cubic, BCC, FCC) with
diagrams. State the number of atoms per unit cell in each.
Q.18 Explain the different types of cubic unit cells (Simple Cubic, BCC, FCC) with
diagrams. State the number of atoms per unit cell in each.
Q.19 Classify solids based on bonding: molecular, ionic, covalent, and metallic. State two
properties and one example of each.
Q.20 Derive the formula to calculate the density of a unit cell.
ALL THE BEST
