Halogens are highly reactive nonmetal elements in group 17 of the periodic table.
Halogens include solids, liquids, and gases at room temperature, and they vary in color.
Halogens are among the most reactive of all elements. They have seven valence electrons, so they are very “eager” to gain one electron to have a full outer energy level.
Halogens have a variety of important uses, such as preventing tooth decay and killing germs.
