Glossary – V

VSEPR Theory: See Valence Shell Electron Pair Repulsion Theory.

Vacancy: A hole, corresponding to a missing ion, in the ideal structure of a solid.

Valence Band: The band in extended molecular orbital theory made up from the valence molecular orbitals on the individual species. It is the highest occupied extended molecular orbital.

Valence Shell Electron Pair Repulsion Theory: This theory describes how the structure of a molecule can be predicted from the number of pairs of bonded electrons and non-bonded electrons in the valence shell of the molecule.

Van der Waals Equation: A modified version of the perfect gas equation, which takes into account the fact that in a real gas, particles do occupy space and do interact.

Van der Waals Forces: Attractive forces that arise between particles as a result of momentary imbalances in the distribution of electrons in the particles. These imbalances produce fluctuating dipoles that can induce similar dipoles in nearby particles, generating a net attractive force.

Vapour Pressure: The pressure of a vapour in equilibrium with its liquid; the pressure at which a liquid is in equilibrium with its vapour.

Vector Model: A general model, in which vectors can be used to represent quantities such as forces, magnetic moments, etc. The direction of the vector specifies the direction of the quantity, and the magnitude of the quantity is given by the length of the vector.

Vinylic: The vinylic position on a molecule is shown here;

Volatile: With low boiling point.

Volatility: A measure of the vapour pressure of a substance. The higher the volatility, the higher the vapour pressure.