Liquids and Solids
Solids
Objectives
1. Explain the properties of solids according to the
KMT.
2. Distinguish between amorphous and crystalline
solids.
3. Define crystal structure and unit cell.
Solids
• Definite shape
• Definite volume
• Intermolecular forces
have a large effect;
particles are held in
fixed positions
Properties of Solids
Definite melting point
• Temperature at which the particles of a solid
overcome intermolecular forces that hold them in
fixed positions
• Freezing points and melting points have the same
values
• Amorphous do not have a definite melting point.
Properties of Solids
High Density
• Particles of solid are packed close together as a result
of low K.E. and high intermolecular forces.
Incompressibility
• Particles cannot be pressed into a smaller volume.
Low Rate of Diffusion
• Result of limited particle movement and limited space
between particles
Crystalline Solids
• Solids in which the
particles are arranged in
an orderly geometric
pattern
• Arrangement of
particles is called a
crystal lattice
• The simplest portion of
the lattice is called the
unit cell
Types of Crystalline Solids
Ionic
• Ionic bonds between anions and cations
Covalent Network
• Covalent bonds between atoms.
• Examples: Diamond (Cx), quartz (SiO2)x,
Metallic
• Metal cations surrounded by a see of electrons
Molecular covalent
• Molecules held together by intermolecular forces
(disperson, dipole-dipole, hydrogen bonding
Types of Crystalline Solids
Amorphous Solids
• Particles are arranged
randomly
• Sometimes referred to
as supercooled liquids
• Examples include glass,
rubber, plastics.