Any of the group of non metallic elements, fluorine, bromine, chlorine, iodine and astatine. They are missing an electron from their outer most shell and react with most elements to form salts
The phyla within the kingdom Archaebacteria include Euryarchaeota, Crenarchaeota, Korarchaeota, Nanoarchaeota, Thaumarchaeota, and Aigarchaeota. These phyla represent the diverse evolutionary lineages within the domain Archaea.
The halogens are located in Group 17 of the periodic table. They include elements such as fluorine, chlorine, bromine, iodine, and astatine. Halogens are highly reactive nonmetals with seven valence electrons.