Reactive

ree-AK-tiv /riˈæktɪv/
adjectiveC1GRESAT
FormalScientific

Tending to undergo a chemical reaction, or responding to a stimulus.

In chemistry, 'reactive' describes a substance's propensity to participate in chemical changes, often indicating instability or a strong desire to form new bonds.

The story behind the word. The word 'reactive' comes from the Latin prefix 're-' meaning 'back' or 'again,' combined with the Latin verb 'agere,' meaning 'to do' or 'to act.' So, to 'react' is to 'act back' or 'act in response.' In chemistry, this describes how substances 'act back' or respond to other substances by undergoing chemical change.

Word relationships

  • Volatile: Implies easily evaporated or explosive, often due to high reactivity.
  • Unstable: Lacking stability, often leading to reactivity.
  • Inert: Chemically unreactive; lacking the ability or strength to move.
  • Stable: Not easily decomposed or changed chemically; resistant to change.

Word family

  • react (verb): To act in response to something; to undergo a chemical change.
  • reactivity (noun): The state or quality of being reactive.
  • reaction (noun): A chemical change; a response to a stimulus.

Collocations

  • highly reactive
  • chemically reactive
  • reactive oxygen species
  • less reactive

Example sentences

  • "Sodium is an extremely reactive metal that bursts into flame upon contact with water." Sodium is a very reactive metal.
  • "Scientists are developing less reactive materials for medical implants to prevent adverse reactions in the body." The new drug was highly reactive.

Memory hook

Think of a 'reactive' substance as one that's ready to 're-act' or respond quickly in a chemical way. Ready to re-act

When not to use

Do not use 'reactive' to describe something that is merely responsive or quick to act without the implication of chemical change or a strong tendency towards it.

Fun facts

  • The reactivity of an element is largely determined by its electron configuration, especially the number of valence electrons.
  • Noble gases like Helium and Neon are known for being highly unreactive, or 'inert,' due to their stable electron shells.

Related words

Catalyst, Oxidation

LangBlitz
Take your vocabulary further with LangBlitz

Our English vocabulary app: FSRS spaced repetition, 5,000+ curated words across 119 topic groups, CEFR A1 to C2. Explore your mastery with the beautiful Vocabulary World feature.