User:Double sharp/Halogen

Template:Periodic table (halogens) The halogens are a group (column) in the periodic table consisting of the chemical elements fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and possibly also the synthetic element tennessine (Ts). This group lies in the p-block of the periodic table of elements as all halogens have seven valence electrons, arranged in the electron configuration ns²np⁵. Since all the halogens are one electron short of a full octet, they exhibit well-characterised homologous behaviour and provide one of the the best examples of group trends in properties in the periodic table.