-all non metals with coloured vapours
-fluorine, very reactive, yellow gas
-chlorine, fairly reactive, dense green gas
-bromine, dense, poisonous, red brown liquid
-iodine, dark grey crystalline solid or purple vapour
-as you go down the group they become less reactive, have higher melting and boiling points, all have 7 electrons in outer shell, higher relative atomic mass
-form ionic bonds with metals
-share electrons through covalent bonding