ioonide

Ioonid, in Estonian, translates to ions in English. They are atoms or molecules that carry a net electric charge due to loss or gain of electrons. The charge is positive in cations and negative in anions. Polyatomic ions are composed of several atoms with an overall charge, such as ammonium NH4+ or sulfate SO4^2-.

Ions form through ionization (removal of electrons) or reduction (gain of electrons) and can arise in chemical reactions, high-energy irradiation, or during electrolysis. They exhibit mobility in electric fields, enabling conductivity in electrolytes and melts. In crystals, ions form ionic compounds with strong electrostatic attraction, yielding high melting points and brittle solids. When dissolved in water or other solvents, many ionic compounds dissociate into hydrated ions.

Common examples include sodium ions Na+, potassium K+, calcium Ca2+, chloride Cl-, and carbonate CO3^2-. The balance of cations and anions in a solution determines electrical neutrality, though changing the ratio affects pH and osmolarity in biological systems.

Applications include electrolytic processes such as electroplating and chlorine production; energy storage in batteries and supercapacitors; water treatment and nutrient transport in biology. In living organisms, ions regulate nerve impulses, muscle contraction, enzyme activity, and fluid balance.

Note: The term ioonide is the Estonian genitive plural form referring to ions.