early 15c., "extract, preparation," from Latin valentia "strength, capacity," from valentem (nominative valens), present participle of valere "be strong" (see valiant). Meaning "combining power of an element" is recorded from 1884, from German Valenz (1868), from the Latin word.
valence va·lence (vā'ləns) or va·len·cy (-lən-sē)
The combining capacity of an atom or a radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.
A positive or negative integer used to represent this capacity.
The number of components of an antigen molecule to which an antibody molecule can bind.
The attraction or aversion that an individual feels toward a specific object or event.
A whole number that represents the ability of an atom or a group of atoms to combine with other atoms or groups of atoms. The valence is determined by the number of electrons that an atom can lose, add, or share. An atom's valence is positive if its own electrons are used in forming the bond, or negative if another atom's electrons are used. For example, a carbon atom can share four of its electrons with other atoms and therefore has a valence of +4. A sodium atom can receive an electron from another atom and therefore has a valence of -1. (In this book the distinction between positive and negative valences is ignored unless it is relevant.) The valence of an atom generally indicates how many chemical bonds it is capable of forming with other atoms. Also called valence number, oxidation state.