Group of elements when in ionic form may associate in salt formation.
Halogens is the reactive nonmetals that are in Group 17 of the periodic table (F, Cl, Br, I, and At). Compounds of these elements are called halogenides or halides.
The chemical elements either individually or collectively that constitute Group VIIA of the periodic table: namely, fluorine, chlorine, bromine iodine and astatine. Of these, only chlorine and bromine are used as disinfectant and sanitizers in pool and spas.