What Group Does Fluorine Belong To?

Fluorine belongs to group number 17, which is the halogen family of elements that also includes astatine, iodine, bromine and chlorine. The element fluorine is a highly reactive gas at room temperature that is not found freely in nature. Fluorine has a melting point of 363.32 degrees F, a boiling point of 306.62 degrees F and a density of 0.001696 grams per cubic centimeter.

Fluorine has an atomic weight of 18.9984032 and is assigned the period number 2 and atomic number 9 on the periodic table of elements. Fluorine is an ingredient in toothpaste and is also widely used in city water supplies in a quantity of one part per million to aid in the prevention of tooth decay.