V

The theory that describes covalent bonding in terms of the overlap of atomic orbitals on different atoms.

valence electron

Any of the electrons found in the highest occupied shell of electrons of the neutral atom.

valence-shell electron-pair repulsion theory

A means of predicting the structures of simple ions and molecules by a simple scheme for counting the number of pairs of electrons in the valence shell of the center atom.

van der Waals equation

An equation describing the behavior of gases and taking into account the effects of non-ideal behavior such as the non-negligible size of molecules of gas and forces of attraction between the molecules.

van der Waals force

Any of the attractive forces between polar or non-polar molecules; also used in the same sense as dispersion force.

vapor

The gaseous state of a substance that typically exists as a liquid or solid.

vapor pressure

The pressure exerted by the gaseous form of a substance above the liquid form.

vaporization

The formation of a vapor from a liquid; evaporation.

viscosity

The extent to which a liquid resists flow.

voltaic cell

An electrochemical cell in which a spontaneous reaction occurs. Such a cell can be used to generate electricity. Also called Galvanic cell.

VSEPR theory

Abbreviation for valence-shell electron-pair repulsion theory; a means of predicting the structures of simple ions and molecules by a simple scheme for counting the number of pairs of electrons in the valence shell of the center atom.

vulcanization

A process that adds substances to rubber in order to change its physical properties.