Science, Tech, Math › Science List of Halogens (Element Groups) Share Flipboard Email Print bubaone / Getty Images Science Chemistry Periodic Table Basics Chemical Laws Molecules Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated December 23, 2018 The halogen elements are located in group VIIA of the periodic table, which is the second-to-last column of the chart. This is a list of elements that belong to the halogen group and the properties that they share in common: Types of Halogens Depending on who you ask, there are either 5 or 6 halogens. Fluorine, chlorine, bromine, iodine, and astatine definitely are halogens. Element 117, which has the placeholder name of ununseptium, might have some properties in common with the other elements. Even though it is in the same column or group of the periodic table with the other halogens, most scientists believe element 117 will behave more like a metalloid. So little of it has been produced, it's a matter of prediction, not empirical data. FluorineChlorineBromineIodineAstatineTennessine (might behave as a halogen, at least in some respects) Halogen Properties These elements share some common properties that distinguish them from other elements on the periodic table. They are highly reactive nonmetals.Atoms of belonging to the halogen group have 7 electrons in their outermost (valence) shell. These atoms need one more electron in order to have a stable octet.Halogens are highly electronegative, with high electron affinities.The melting and boiling points of the halogens increase as you increase atomic number (as you move down the periodic table).The elements change their state of matter at room temperature and pressure as you increase atomic number. Fluorine and chlorine are gases. Bromine is a liquid element. Iodine is a solid. Scientists predict tennessine will be a solid at room temperature.