halogeeniin

Halogeeniin is the illative singular form of the Finnish noun halogeeni, which corresponds to the English term halogen. In chemistry, halogens are a group of reactive nonmetal elements found in group 17 of the periodic table. The classic halogens are fluorine, chlorine, bromine, iodine, and astatine; a seventh, tennessine, is a synthetic member of the group.

Characteristics: Halogens are highly reactive, with high electronegativity and a tendency to form salts with alkali metals. In elemental form they occur as diatomic molecules: F2, Cl2, Br2, and I2 (solid at room temperature for iodine). The reactivity generally decreases down the group from fluorine to tennessine. They readily gain one electron to form halide ions and participate in a wide range of reactions, including combustion, substitution, and oxidation reactions. They have distinct physical states at room temperature: fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid; astatine and tennessine are short-lived in practice.

Occurrence and uses: Halogens occur in minerals and in seawater, with chlorine and fluorine widely extracted for industrial use. Chlorine is used for water disinfection and in manufacturing; fluorides strengthen tooth enamel; iodine is essential in nutrition; bromine is used in flame retardants and certain pharmaceuticals; astatine and tennessine are primarily of scientific interest due to instability and scarcity.

Safety: Halogens are reactive and can be toxic or corrosive in certain forms. They should be handled with appropriate containment and protective equipment; many halogens form corrosive gases or acids when released.

Linguistic note: In Finnish grammar, halogeeniin denotes the illative case “into/onto the halogen” and is not a distinct chemical concept; the chemistical concept is described by halogeeni or halogeenit, depending on number.