Wikipedia, Aug. 27, 2012: Nonmetal (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; In Group 14: carbon (C); In Group 15 (the pnictogens): nitrogen (N), phosphorus (P); In Group 16 (the chalcogens): oxygen (O), sulfur (S), selenium (Se); All elements (with the possible exception of ununseptium) in Group 17 -- the halogens; All elements (with the possible exception of ununoctium) in Group 18 -- the noble gases)

Chemical Elements.com : an online, interactive periodic table of the elements, viewed Aug. 27, 2012: Non-Metals (Non-metals are the elements in groups 14-16 of the periodic table. Non-metals are not able to conduct electricity or heat very well. As opposed to metals, non-metallic elements are very brittle, and cannot be rolled into wires or pounded into sheets. The Non-Metal elements are: Hydrogen, Carbon, Nitrogen, Oxygen, Phosphorus, Sulfur, Selenium)

Helmenstine, A.M. Nonmetals : properties of element groups, via About.com Chemistry website, Aug. 27, 2012 (The nonmetals are located on the upper right side of the periodic table. Nonmetals are separated from metals by a line that cuts diagonally through the region of the periodic table containing elements with partially filled p orbitals. Technically the halogens and noble gases are nonmetals, but the nonmetal element group usually is considered to consist of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, and selenium.)

Nonmetals, 2004.