Halogen

The halogens are chemical elements under the second-to-right column in the periodic table, also known as Group 17. The elements in the group are fluorine, chlorine, bromine, iodine, astatine, and tennessine. Halogen literally means "salt becomer", but it is often said to mean "salt producer". They are very reactive, so they are likely to join with other elements on the left side of the periodic table to make compounds. This is because they are missing one electron. They are rarely found alone in nature.

Fluorine is the most reactive, while the rest of the halogens become less reactive. Iodine is the least reactive, and Astatine is very radioactive and hard to get. Only atoms of Tennessine are made in a lab, so chemistry on it is not well known. Every element is either toxic or dangerous in some way, as it does not take much to kill a person, but each one can form an important salt that everyone uses every day, like table salt (Sodium Chloride). Iodine is also an important element in the diets of many.