halógenahópurinn

The halogens, also known as the halógenahópurinn in Icelandic, are a group of chemical elements comprising the seventh column of the periodic table. This group includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are characterized by their high reactivity and their tendency to form salts, hence the name "halogen" which means "salt-former" in Greek.

Halogens exist as diatomic molecules in their elemental state, meaning they consist of two atoms bonded together, such as F2, Cl2, Br2, and I2. Their physical properties vary significantly within the group. Fluorine is a pale yellow gas, chlorine is a greenish-yellow gas, bromine is a reddish-brown liquid, and iodine is a dark purple solid that readily sublimes into a violet vapor. Astatine is a rare radioactive element and its properties are less well-studied, but it is believed to be a solid.

The high reactivity of halogens stems from their electron configuration. They each have seven valence electrons, requiring only one more electron to achieve a stable electron shell. This makes them strong oxidizing agents, readily accepting an electron from other elements to form halide ions with a charge of -1. This tendency to gain an electron is strongest in fluorine and decreases down the group. Halogens form a wide variety of compounds, including ionic salts and covalent molecules, and are essential in many industrial and biological processes.