# reactivity

/ˌɹiˌækˈtɪvəti/ (US) · /ɹɪɐktˈɪvɪti/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/reactivity
Updated: 2026-05-19

## Definition

the ability of a substance to react with another substance to create a new one. It describes how quickly or easily a chemical change happens.

For teachers: the tendency of a substance to undergo a chemical reaction with another substance. Often used to describe the sensitivity of a material to external stimuli such as heat, light, or pressure.

## Examples

- The reactivity of the metal increases when it is exposed to air.
- Chemists carefully measure the reactivity of different compounds to ensure the reaction remains controlled and safe.
- The high reactivity of the alkali metals necessitates their storage in an inert atmosphere to prevent spontaneous combustion upon contact with moisture.

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