List of alternative nonmetal classes

Metalloid	Unclassified nonmetal	Nonmetal halogen	Noble gas
B, Si, Ge, As, Sb, Te, Po, At	H, C, N, P, O, S, Se	F, Cl, Br, I	He, Ne, Ar, Kr, Xe, Rn
Boron is an example of a metalloid	Oxygen in liquid form	Bromine	A krypton-filled discharge tube glowing white

In chemistry, after nonmetallic elements such as silicon, chlorine, and helium are classed as either metalloids, halogens, or noble gases, the remaining unclassified nonmetallic elements are hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur and selenium.

The nonmetallic elements are sometimes instead divided into two to seven alternative classes or sets according to, for example, electronegativity; the relative homogeneity of the halogens; molecular structure; the peculiar nature of hydrogen; the corrosive nature of oxygen and the halogens; their respective groups; and variations thereupon.