valence

Valence is a term used in several disciplines to denote a common idea: a measure of bonding capacity, emotional value, or the demands a referent places on other elements. Though the word has different technical senses, they share the core notion of “how much” or “what kind of value” a subject holds in a given context.

In chemistry, valence (or valency) refers to the combining capacity of an atom, often linked to the number of electrons available to form bonds. For main-group elements, valence generally corresponds to the group number. Atoms achieve stable structures by sharing, losing, or gaining electrons to complete outer shells. Valence is related to, but not identical with, oxidation state, which is a bookkeeping measure of electron ownership in compounds. Examples include hydrogen with valence 1 and carbon with valence 4.

In solid-state physics and materials science, the term also appears in the concept of valence electrons, which fill the valence band in a solid. The energy gap to the conduction band governs electrical conductivity, with valence electrons playing a central role in bonding and electronic properties.

In linguistics, valence (valency) describes the number and type of arguments a predicate requires. An intransitive verb has valence 1 (subject only), a transitive verb has valence 2 (subject and object), and ditransitive verbs have valence 3 (subject, direct object, and indirect object).

In psychology and affective science, valence indicates the intrinsic attractiveness or aversiveness of an event or object, forming a positive–negative dimension of emotion, often studied alongside arousal.

In political science, valence issues are policies for which there is broad consensus among voters, as opposed to issue-specific, competition-based debates.