Liquids and Solids Solids. Objectives 1.Explain the properties of solids according to the KMT....

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.