Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Nonmetal, or non-metal, is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, every element in the periodic table can be termed either a metal or a nonmetal. (A few elements with intermediate properties are referred to as metalloids). The elements generally regarded as nonmetals are: hydrogen (H). In Group 14: carbon (C). In Group 15 (the pnictogens): nitrogen (N), phosphorus (P). Several elements in Group 16, the chalcogens: oxygen (O), sulfur (S), selenium (S). All elements in Group 17 (Except for Astatine) - the halogens. All elements in Group 18 - the noble gases