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  1. Ion - Wikipedia

    Ions consisting of only a single atom are termed monatomic ions, atomic ions or simple ions, while ions consisting of two or more atoms are termed polyatomic ions or molecular ions.

  2. Ion | Definition, Chemistry, Examples, & Facts | Britannica

    Nov 18, 2025 · Ion, any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged ions are called cations; negatively charged ions, anions. Ions migrate …

  3. What Is an Ion? Definition and Examples - ThoughtCo

    Sep 4, 2019 · Learn the definition of an ion, as used in chemistry, chemical engineering, and physics, plus review examples of ions.

  4. 11.4: Ions and Ion Formation - Chemistry LibreTexts

    Ions are atoms that have a positive or negative charge because they have unequal numbers of protons and electrons. If atoms lose electrons, they become positive ions, or cations.

  5. Ions and Ionic Compounds | Introductory Chemistry - Lumen Learning

    Electrons can move from one atom to another; when they do, species with overall electric charges are formed. Such species are called ions. Species with overall positive charges are termed cations, while …

  6. What Is an Ion? Chemistry Definition - Science Notes and Projects

    Nov 20, 2021 · In chemical reactions, ions form when atoms or molecules gain or lose valence electrons. Only nuclear reactions change the number of protons in a chemical species. The two …

  7. Ion Definition: Meaning, Types, Examples & Key Facts Explained

    Atoms form ions to achieve a more stable electron configuration, typically that of the nearest noble gas. By losing or gaining electrons, an atom can attain a full outermost electron shell (an 'octet'), which is …

  8. Ions Explained: Definition, Examples, Practice & Video Lessons - Pearson

    Ions are atoms that have gained or lost electrons, resulting in a net electrical charge. When an atom loses electrons, it becomes a cation, which is a positively charged ion. Conversely, when an atom …

  9. Ion - Properties, Symbols and Formation | CK-12 Foundation

    Dec 1, 2025 · Ions are atoms that have a positive or negative charge because they have unequal numbers of protons and electrons. If atoms lose electrons, they become positive ions, or cations.

  10. What is an Ion? - BYJU'S

    What is an Ion? An ion can be defined as a chemical species which holds a positive or negative charge of some magnitude. The term ‘ion’ can be used to refer to atoms or molecules that have non-zero net …