Liquids and Solids
Solids
Objectives1. 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 SolidsDefinite 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 SolidsHigh 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 SolidsIonic • 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.