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Chemistry vocabulary · Atoms and the Periodic Table

Ion

Meaning in chemistry, with examples

/ˈaɪən/nounCore term

In chemistry, ion means: An atom or group of atoms that carries an electric charge because it has gained or lost electrons. Positive ones are cations and negative ones are anions.

In Turkish: iyon

How it is used

Used in inorganic chemistry, solutions and analysis. Salts dissolve into ions, ions carry current in solution, and chemists talk about metal ions, spectator ions and polyatomic ions such as sulfate.

Example sentences

  1. When sodium chloride dissolves, it splits into sodium and chloride ions.

  2. Write the net ionic equation and leave out the spectator ions.

Common collocations

  • metal ion
  • spectator ion
  • polyatomic ion
  • hydroxide ion
  • ion concentration
  • cationAn ion with a positive charge, formed when an atom or group of atoms loses electrons. Na⁺, Ca²⁺ and NH₄⁺ are examples.
  • anionAn ion with a negative charge, formed when an atom or group of atoms gains electrons. Cl⁻, OH⁻ and SO₄²⁻ are examples.
  • electronA tiny particle with a negative charge that moves around the nucleus of an atom. Chemical bonds and reactions are mostly about how these particles are shared or transferred.
  • ionic bondThe strong attraction between positive and negative ions that forms when one atom, usually a metal, transfers electrons to another, usually a nonmetal. Sodium chloride is the classic case.
  • saltAn ionic compound made of positive and negative ions, usually formed when an acid reacts with a base. Sodium chloride is the best known, but there are thousands of others.

More terms: Atoms and the Periodic Table

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