Crystalline solids have a regular, repeating arrangement of particles that gives them distinct properties including: - Sharp melting points as they melt at specific temperatures - Anisotropic properties that vary in different directions Amorphous solids lack long-range order and instead have a random, unordered structure. As a result, they exhibit: - A gradual softening and flowing over a temperature range without a distinct melting point - Uniform properties in all directions Some key examples of each are crystalline solids like NaCl, metals, and diamonds and amorphous solids such as glass, plastic, and rubber.

2. Solid State
Solid state characterized
by strong interparticle
forces.
Solids have definite shape
and volume.
Shape and volume change
slightly with temperature
and pressure.
Smallest constituent
particles: atoms, ions, or
molecules.
These particles referred to
as 'particles' in this
chapter.

3. Types of Solids
Crystalline
Solid
Amorphous
Solid

4. Crystalline Solid
• A crystalline solid is a type of
material that is made up of tiny
particles arranged in a regular,
repeating pattern, like the way
bricks are stacked neatly in a
wall.

5. Properties of Crystalline Solid
Crystalline solids: Regular, repeating particle
arrangement.
Sharp melting points: They melt at specific
temperatures.
Anisotropic properties: Varying characteristics
in different directions.
Examples: Ice, salt (like NaCl), metals (sodium,
gold, copper), diamond, graphite, ceramics

6. Q. Why are crystalline Solid
Anisotropic? 2010
Ans: Crystalline solids are anisotropic because their
properties vary with direction due to the orderly
arrangement of atoms or molecules in the crystal
lattice. This means that the properties like refractive
index, thermal, and electrical conductivity differ
depending on the direction in which they are
measured within the crystal structure.

7. Amorphous
solids
• An amorphous solid is a substance lacking a defined,
repeating arrangement of particles, resulting in a
random and unordered structure. Examples include
glass, plastic, and some types of rubber.

8. Properties of
Amorphous Solid
• Random arrangement: Particles in
amorphous solids lack long-range order but
have short-range order.
• Gradual melting: They soften and flow
gradually over a temperature range upon
heating, without sharp melting points.
• Uniform properties: Amorphous solids
exhibit consistent properties in all directions.
• Examples: Glass, plastic, rubber, tar, and
metallic glass.

9. Distinguish between crystalline solids and
Amorphous Solids. [13,14,17,19]