Halogens are classified as nonmetals. This group of elements includes fluorine, chlorine, bromine, iodine, and astatine. Nonmetals are typically characterized by their lack of metallic luster, poor conductivity of heat and electricity, and the ability to gain or share electrons in chemical reactions.
Specifically, halogens are situated in Group 17 of the periodic table, and they are known for having seven electrons in their outermost shell. This configuration makes them highly reactive, as they seek to gain one more electron to achieve a stable octet configuration. Their high reactivity sets them apart from metals, which tend to lose electrons easily.
While metals form cations by losing electrons, halogens, being nonmetals, tend to form anions by gaining electrons. Therefore, halogens are definitively categorized as nonmetals, characterized by their unique properties and behaviors in chemical reactions.