Structure and Properties of Solids in Chemistry

Crystalline solid

Particles are in an orderly, repeating pattern (examples - aluminum, salt).

Amorphous solid

Particles are not arranged in an orderly pattern (examples - glass, wax).

Metallic solid

Held together by positive metal nuclei in a sea of electrons; good electrical conductors because electrons are free to move around; malleable.

Ionic solid

Held together by cubes of positive and negative ions electrostatically attracted; good electrical conductors when melted or in water; have high melting points.

Molecular solid

Held together by weak intermolecular forces; poor electrical conductors because there are no ions; have low melting points.

Covalent Network solid

Held together by a large network of directional covalent bonds; acts like one giant molecule; have high melting points.

Kinetic energy

The energy an object has because of its motion.

Kinetic theory

Theory explaining the states of matter, based on the concept that the particles in all forms of matter are in constant motion.

Gas Pressure

The force exerted by a gas per unit surface area of an object; due to collisions of gas particles with the object.

Vacuum

A space where no particles of matter exist.

Atmospheric Pressure

The pressure exerted by air molecules in the atmosphere surrounding Earth, resulting from collisions of air molecules with objects.

Barometers

An instrument used to measure atmospheric pressure.

Pascal (Pa)

The SI unit of pressure.

Standard Atmosphere (atm)

A unit of pressure; it is the pressure required to support 760 mm Hg in a barometer at 25 °C; this is the average atmospheric pressure at sea level.

London - Dispersion

Weakest intermolecular force, experienced by all, only experienced by non-polar molecules.

Dipole-Dipole

Medium intermolecular force, experienced by all polar molecules.

Hydrogen Bonding

Strongest intermolecular force, occurs between H and F, O, or N.

Vapor Pressure

The pressure exerted by a vapor in equilibrium with its liquid or solid form.

Endothermic

A process in which heat is absorbed.

Exothermic

A process in which heat is released.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the surrounding pressure.