A solid consisting of positive and negative ions arranged into crystals that are made up of regularly
repeated units and held together by ionic bonds.
Ionization energy
The energy required to remove an electron from the valence shell of a gaseous atom.
Ionization product
The general term for the dissociation of salts or of weak acids or bases; the ratio of the
concentration of the ionic products to the concentration of the reactant for a reaction, all raised to
their stoichiometric coefficients.
Isobaric process
A process that occurs at constant pressure.
Isolated system
A system that can exchange neither matter nor energy with its surroundings.
Isomers
Compounds with the same molecular formula but different structures.
Isothermal process
A process that occurs at constant temperature.
Isotopes
Atoms containing the same number of protons but different numbers of neutrons; e.g., nitrogen-14
and nitrogen-15.
Joule (J)