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chemical elementelement,
in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means of a chemical reaction, but no further simplification can be achieved.
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 possessing certain properties by which it is distinguished from a metalmetal,
chemical element displaying certain properties by which it is normally distinguished from a nonmetal, notably its metallic luster, the capacity to lose electrons and form a positive ion, and the ability to conduct heat and electricity.
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. In general, this distinction is drawn on the basis that a nonmetal tends to accept electrons and form negative ionsion,
atom or group of atoms having a net electric charge. Positive and Negative Electric Charges

A neutral atom or group of atoms becomes an ion by gaining or losing one or more electrons or protons.
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 and that its oxide is acidic. Nonmetals are poor conductors of heat and electricity (see conductionconduction,
transfer of heat or electricity through a substance, resulting from a difference in temperature between different parts of the substance, in the case of heat, or from a difference in electric potential, in the case of electricity.
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) and do not have the luster of metals. Arsenic, antimony, selenium, and tellurium exhibit both nonmetallic and metallic properties and are called metalloids. Unlike the metals, which are all solids (with the exception of mercury) under ordinary conditions of temperature and pressure, the nonmetals appear in all three states. Argon, chlorine, fluorine, helium, hydrogen, krypton, neon, nitrogen, oxygen, and xenon are normally gases. Bromine is a liquid. Boron, carbon, iodine, phosphorus, silicon, and sulfur are solids. Certain of them, e.g., boron, carbon, iodine, silicon, and sulfur, form crystals, as do the metals. In hardness they vary considerably. Carbon in its allotropic form, the diamond, is the hardest element known. With the exception of carbon, sulfur, nitrogen, oxygen, and the inert gases—argon, helium, krypton, neon, and xenon—the nonmetals do not occur uncombined in nature, but exist in numerous relatively abundant compounds, among which are the oxides, halides (binary halogen compounds), sulfides, carbonates, nitrates, phosphates, silicates, and sulfates. With a few exceptions, the nonmetallic elements are important chiefly for their compounds. For the properties and uses of specific nonmetals, see the separate articles on these elements.
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any of a number of chemical elements that form negative ions, have acidic oxides, and are generally poor conductors of heat and electricity
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Johnson knew that laser cutting is not always the best tool for some jobs and was interested in purchasing a waterjet cutting system for certain high-precision jobs and non-metal cutting.
The conditions in this level include uncomplicated metal shapes (no non-metal substrates of significance); few colors to meet most of demand; the level of smoothness (orange peel, appearance) was acceptable; relatively wide variations of dry film thicknesses were ok--1.5-3.5 mils on same object was acceptable as was the economics; and the toughness of the powder coating was superior to the incumbent liquid/porcelain targets.
Biochemists and other scientists from the chemical or biological hinterlands describe some recent developments in remediating non-metal pollutants in soil, ground water, and marine environments.
has been named as a Visteon Important Partner, exemplifying "best in class" performance as a North American non-metals supplier.
This peak can create many problems, both with metals and non-metals so at least one manufacturer is considering an oil-cooler to minimize upper temperatures to 125 degrees C.
The plant includes a pre-washer followed by two Steinert eddy currents and a media drum that uses magnetite to separate the remaining metals from non-metals. A double-density drum helps separate lighter magnesium metals from heavier aluminum metals and from metals that are heavier yet (copper, brass, zinc).