halojeni

Halogens are a group of chemical elements that constitute Group 17 of the periodic table. The name "halogen" is derived from the Greek words "hals" meaning salt and "gen" meaning to form, as they readily form salts with metals. This group consists of five non-metallic elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Tennessine (Ts) is also provisionally placed in this group.

These elements are highly reactive and possess similar chemical properties. They are all diatomic molecules in their elemental form, meaning they exist as pairs of atoms bonded together (e.g., F₂, Cl₂, Br₂, I₂). As you move down Group 17, the atomic radius increases, and electronegativity decreases. Their reactivity also tends to decrease from fluorine to iodine. Halogens typically gain one electron to achieve a stable electron configuration, forming negatively charged halide ions with a charge of -1.

Fluorine is the most electronegative and reactive of all elements. Chlorine is a yellowish-green gas used in disinfectants and bleaching. Bromine is a reddish-brown liquid that is volatile and toxic. Iodine is a solid that sublimes into a purple vapor and is essential for thyroid function. Astatine is a rare, radioactive element with few known properties. Halogen compounds are widespread in nature and industry, playing roles in everything from pharmaceuticals and plastics to water purification and nutrition.