va|lence

va|lence «VAY luhns», noun.

1. Chemistry. a) the capacity of an atom or radical to combine with other atoms or radicals, determined by the number of electrons that an atom will lose, add, or share when it reacts with other atoms. Elements whose atoms lose electrons, such as hydrogen and the metals, have a positive valence. Elements whose atoms add electrons, such as oxygen and other nonmetals, have a negative valence. b) a unit of valence: »

Oxygen has two valences.

2. Biology. a) the ability of serums and other organic substances to interact or produce a certain effect. b) the ability of chromosomes to unite with or produce a certain effect upon each other.

╂[< Latin valentia strength, capacity < valēns, -entis, present participle of valēre be strong]