S: (n) fluorine, F, atomic number 9 (a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite)
S: (n) chemical element, element (any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter)
S: (n) allotrope (a structurally different form of an element) "graphite and diamond are allotropes of carbon"
S: (n) transuranic element (any element having an atomic number greater than 92 (which is the atomic number of uranium); all are radioactive)
S: (n) metallic element, metal (any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.)
S: (n) nonmetal (a chemical element lacking typical metallic properties)
S: (n) transactinide (any of the artificially produced elements with atomic numbers greater than 103)
S: (n) argon, Ar, atomic number 18 (a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere)
S: (n) arsenic, As, atomic number 33 (a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar)
S: (n) astatine, At, atomic number 85 (a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium)
S: (n) boron, B, atomic number 5 (a trivalent metalloid element; occurs both in a hard black crystal and in the form of a yellow or brown powder)
S: (n) bromine, Br, atomic number 35 (a nonmetallic heavy volatile corrosive dark brown liquid element belonging to the halogens; found in sea water)
S: (n) carbon, C, atomic number 6 (an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds)
S: (n) chlorine, Cl, atomic number 17 (a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water))
S: (n) fluorine, F, atomic number 9 (a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite)
S: (n) germanium, Ge, atomic number 32 (a brittle grey crystalline element that is a semiconducting metalloid (resembling silicon) used in transistors; occurs in germanite and argyrodite)
S: (n) helium, He, atomic number 2 (a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas))
S: (n) hydrogen, H, atomic number 1 (a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe)
S: (n) iodine, iodin, I, atomic number 53 (a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks))
S: (n) mendelevium, Md, Mv, atomic number 101 (a radioactive transuranic element synthesized by bombarding einsteinium with alpha particles (Md is the current symbol for mendelevium but Mv was formerly the symbol))
S: (n) neon, Ne, atomic number 10 (a colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts)
S: (n) nitrogen, N, atomic number 7 (a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues)
S: (n) nobelium, No, atomic number 102 (a radioactive transuranic element synthesized by bombarding curium with carbon ions; 7 isotopes are known)
S: (n) oxygen, O, atomic number 8 (a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust)
S: (n) phosphorus, P, atomic number 15 (a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms)
S: (n) plutonium, Pu, atomic number 94 (a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239)
S: (n) radon, Rn, atomic number 86 (a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health)
S: (n) selenium, Se, atomic number 34 (a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite))
S: (n) silicon, Si, atomic number 14 (a tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors)
S: (n) sulfur, S, sulphur, atomic number 16 (an abundant tasteless odorless multivalent nonmetallic element; best known in yellow crystals; occurs in many sulphide and sulphate minerals and even in native form (especially in volcanic regions))
S: (n) tellurium, Te, atomic number 52 (a brittle silver-white metalloid element that is related to selenium and sulfur; it is used in alloys and as a semiconductor; occurs mainly as tellurides in ores of copper and nickel and silver and gold)
S: (n) chlorine, Cl, atomic number 17 (a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water))
S: (n) fluorine, F, atomic number 9 (a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite)
S: (n) hydrogen, H, atomic number 1 (a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe)
S: (n) nitrogen, N, atomic number 7 (a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues)
S: (n) oxygen, O, atomic number 8 (a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust)
S: (n) butane (occurs in natural gas; used in the manufacture of rubber and fuels)
S: (n) propane (colorless gas found in natural gas and petroleum; used as a fuel)
S: (n) afterdamp (a toxic mixture of gases (including carbon dioxide and carbon monoxide and nitrogen) after an explosion of firedamp in a mine)
S: (n) firedamp (a mixture of gases (mostly methane) that form in coal mines and become explosive when mixed with air)
S: (n) arsine (a poisonous colorless flammable gas used in organic synthesis and to dope transistors and as a poison gas in warfare)
S: (n) air (a mixture of gases (especially oxygen) required for breathing; the stuff that the wind consists of) "air pollution"; "a smell of chemicals in the air"; "open a window and let in some air"; "I need some fresh air"
S: (n) ethylene, ethene (a flammable colorless gaseous alkene; obtained from petroleum and natural gas and used in manufacturing many other chemicals; sometimes used as an anesthetic)
S: (n) producer gas, air gas (a gas made of carbon monoxide and hydrogen and nitrogen; made by passing air over hot coke)
S: (n) methane (a colorless odorless gas used as a fuel)
S: (n) ozone (a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation))
S: (n) phosgene (a colorless poisonous gas that smells like new-mown hay; used in chemical warfare)
S: (n) phosphine (a colorless gas with a strong fishy smell; used as a pesticide)
S: (n) poison gas (a gas that is poisonous to breath or contact; used in chemical warfare)
S: (n) propylene, propene (a flammable gas obtained by cracking petroleum; used in organic synthesis)
S: (n) mephitis (a poisonous or foul smelling gas emitted from the earth)
S: (n) sulfur dioxide, sulphur dioxide (a colorless toxic gas (SO2) that occurs in the gases from volcanoes; used in many manufacturing processes and present in industrial emissions; causes acid rain)
S: (n) halogen (any of five related nonmetallic elements (fluorine or chlorine or bromine or iodine or astatine) that are all monovalent and readily form negative ions)
S: (n) astatine, At, atomic number 85 (a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium)
S: (n) bromine, Br, atomic number 35 (a nonmetallic heavy volatile corrosive dark brown liquid element belonging to the halogens; found in sea water)
S: (n) chlorine, Cl, atomic number 17 (a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water))
S: (n) fluorine, F, atomic number 9 (a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite)
S: (n) iodine, iodin, I, atomic number 53 (a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks))
S: (n) farad, F (the capacitance of a capacitor that has an equal and opposite charge of 1 coulomb on each plate and a voltage difference of 1 volt between the plates)