Where are nonmetals located on the periodic table?

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Nonmetals on the periodic table are located in the upper right corner, to the right of the stair-step line that separates them from the metals, with one exception: hydrogen, which sits at the top left above group 1 but behaves as a nonmetal. Most of the nonmetals fill the right side of the p-block, in groups 14 to 18. Carbon is in group 14, nitrogen and phosphorus in group 15, oxygen, sulfur and selenium in group 16, the halogens (fluorine, chlorine, bromine and iodine) in group 17, and the noble gases (helium, neon, argon, krypton, xenon and radon) in group 18. That makes 17 elements in the usual count: hydrogen, helium, carbon, nitrogen, oxygen, fluorine, neon, phosphorus, sulfur, chlorine, argon, selenium, bromine, krypton, iodine, xenon and radon. Oganesson (element 118) also sits in group 18 but is usually left out of the count because its properties are only predicted. The metalloids, boron, silicon, germanium, arsenic, antimony and tellurium, lie along the staircase between the two regions, so the nonmetals are always found on the upper-right side of it. Nonmetals are the opposite of metals in most of their properties. They are poor conductors of heat and electricity, their solids are brittle and dull instead of malleable and shiny, and they have lower melting points and densities. They also have high electronegativity and high ionization energy, so their atoms tend to gain or share electrons instead of losing them, and fluorine is the most electronegative element of all. Nonmetals also include every element that is a gas at room temperature: all eleven gases at 25 °C are nonmetals, and bromine is the one liquid nonmetal. Carbon, phosphorus, sulfur, selenium and iodine are solids. Despite being a small part of the table, nonmetals make up most of living matter and the atmosphere, since carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur are the elements of biological molecules and air is mostly nitrogen and oxygen. To find them on any periodic table, locate boron at the top of the staircase, follow the line down to tellurium, and every element to its right, plus hydrogen, is a nonmetal.