I

Ion

M^n± (cation or anion); formed by electron gain/loss or bond heterolysis
Quick Reference
Formula / NotationM^n± (cation or anion); formed by electron gain/loss or bond heterolysis
Also Known AsCation (positive), anion (negative), charged species, ionic species

What is Ion?

An atom or molecule that has gained or lost one or more electrons, acquiring a net electric charge. Cations (positive ions) have lost electrons; anions (negative ions) have gained electrons. Ions are formed in ionic compounds and are present in electrolyte solutions.

Formula & Notation

M^n± (cation or anion); formed by electron gain/loss or bond heterolysis

Other Names / Synonyms: Cation (positive), anion (negative), charged species, ionic species

Properties & Characteristics

An ion is an atom or group of atoms that has gained or lost one or more electrons, resulting in a net electrical charge. Positively charged ions (cations) result from electron loss; negatively charged ions (anions) from electron gain. Ions are formed by ionisation (removal of electrons from neutral atoms by high energy processes), by heterolytic bond cleavage, or by proton transfer in acid-base reactions. In solution, ions are surrounded by solvent molecules (hydrated in water).

Uses & Applications

Ions are fundamental to: all electrochemistry (electrolysis, batteries, fuel cells), biology (Na⁺, K⁺, Cl⁻ in nerve impulse; Ca²⁺ in bone; Fe²⁺/³⁺ in haemoglobin and enzymes), industrial processes (ionic liquids as solvents, ion exchange in water treatment), and analytical chemistry (ion chromatography, mass spectrometry of ions).

Safety Information

Ion toxicity varies enormously: Na⁺ essential; Hg²⁺, Pb²⁺, Cd²⁺ highly toxic heavy metal ions; F⁻ toxic at high concentrations. Ions of strong acids at high concentration produce corrosive solutions. Ion-containing compounds require individual SDS review for hazard determination.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Ion
Formula M^n± (cation or anion); formed by electron gain/loss or bond heterolysis
Synonyms Cation (positive), anion (negative), charged species, ionic species

Frequently Asked Questions

An atom or molecule that has gained or lost one or more electrons, acquiring a net electric charge. Cations (positive ions) have lost electrons; anions (negative ions) have gained electrons. Ions are formed in ionic compounds and are present in electrolyte solutions.

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