polyatomic nonmetal

In the context of the periodic table, a nonmetal is a chemical element that mostly lacks distinctive metallic properties. Physically, nonmetals range from colorless gases such as hydrogen to lustrous crystalline solids such as iodine. They are usually less dense than metals and are often poor conductors of heat and electricity. Chemically, they have moderate to very high electronegativity—a tendency to attract electrons in a chemical bond—and their oxides tend to be acidic.