Halogeeneja

Halogeeneja, from the Greek words "hals" (salt) and "gennan" (to produce), are a group of six elements in the periodic table. These elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). They are located in Group 17 (or VIIA) of the periodic table, characterized by having seven valence electrons. This electron configuration makes them highly reactive, as they readily gain one electron to achieve a stable electron shell, forming negatively charged ions called halide ions.

In their elemental form, halogens exist as diatomic molecules. Fluorine and chlorine are gases at room temperature, bromine is a liquid, and iodine is a solid. Astatine and tennessine are synthetic and radioactive, with very short half-lives, and their chemical properties are less understood. The reactivity of halogens decreases down the group, with fluorine being the most electronegative and reactive element.

Halogens form a wide variety of compounds, many of which are essential for life or have significant industrial applications. For example, sodium chloride (table salt) is a common compound formed between sodium and chlorine. Chlorine is used in water purification and as a disinfectant. Fluorine compounds are found in toothpaste and refrigerants. Bromine is used in flame retardants. Iodine is essential for thyroid hormone production.