Chemical Elements - 3 | Britannica.com
Chemical Elements
any substance that cannot be decomposed into simpler substances by ordinary chemical processes.
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dysprosium Dy chemical element, a rare-earth metal of the lanthanide series of the periodic table. Dysprosium is a relatively hard metal and is silvery white in its pure form. It is quite stable in air, remaining shiny at room temperature. Dysprosium turnings ignite...
einsteinium Es synthetic chemical element of the actinoid series of the periodic table, atomic number 99. Not occurring in nature, einsteinium (as the isotope einsteinium-253) was first produced by intense neutron irradiation of uranium -238 during the detonation...
Ekeberg, Anders Gustav Swedish chemist who in 1802 discovered the element tantalum. After graduation from the University of Uppsala (1788) and travels in Germany, Ekeberg returned to Uppsala and began teaching (1794), introducing the chemistry of Antoine-Laurent Lavoisier....
electrum natural or artificial alloy of gold with at least 20 percent silver, which was used to make the first known coins in the Western world. Most natural electrum contains copper, iron, palladium, bismuth, and perhaps other metals. The colour varies from...
erbium Er chemical element, a rare-earth metal of the lanthanide series of the periodic table. Pure erbium is a silvery white metal that is relatively stable in air. It slowly reacts with water and quickly dissolves in diluted acids, except hydrofluoric acid...
ethyl chloride C 2 H 5 Cl colourless, flammable gas belonging to the family of organohalogen compounds. At one time, ethyl chloride was a high-volume industrial chemical used in the preparation of the gasoline additive tetraethyl lead. Beginning with restrictions on...
ethylene bromide C 2 H 4 Br 2 a colourless, sweet-smelling, nonflammable, toxic liquid belonging to the family of organohalogen compounds. Ethylene bromide was once used in conjunction with lead-containing antiknock agents as a component of gasoline; however, this use...
ethylene chloride C 2 H 4 Cl 2 a colourless, toxic, volatile liquid having an odour resembling that of chloroform. It is denser than water, and it is practically insoluble in water. Ethylene chloride is produced by the reaction of ethylene and chlorine. The annual production...
europium Eu chemical element, a rare-earth metal of the lanthanide series of the periodic table. Europium is the least dense, the softest, and the most volatile member of the lanthanide series. The pure metal is silvery, but after even a short exposure to air...
Fairbairn, Sir William, 1st Baronet Scottish civil engineer and inventor who did pioneering work in bridge design and in testing iron and finding new applications for it. From 1817 to 1832 he was a millwright at Manchester, in partnership with James Lillie. In 1835 he established a shipbuilding...
fermium Fm synthetic chemical element of the actinoid series of the periodic table, atomic number 100. Fermium (as the isotope fermium-255) is produced by the intense neutron irradiation of uranium -238 and was first positively identified by American chemist...
ferrite a ceramic-like material with magnetic properties that are useful in many types of electronic devices. Ferrites are hard, brittle, iron-containing, and generally gray or black and are polycrystalline— i.e., made up of a large number of small crystals....
ferroalloy an alloy of iron (less than 50 percent) and one or more other metals, important as a source of various metallic elements in the production of alloy steels. The principal ferroalloys are ferromanganese, ferrochromium, ferromolybdenum, ferrotitanium, ferrovanadium,...
flerovium Fl artificially produced transuranium element of atomic number 114. In 1999 scientists at the Joint Institute for Nuclear Research in Dubna, Russia, and the Lawrence Livermore National Laboratory in Livermore, California, produced atoms of flerovium...
fluorine F most reactive chemical element and the lightest member of the halogen elements, or Group 17 (Group VIIa) of the periodic table. Its chemical activity can be attributed to its extreme ability to attract electrons (it is the most electronegative element)...
fluorocarbon compound composed of the elements carbon and fluorine; see halocarbon.
francium Fr heaviest chemical element of Group 1 (Ia) in the periodic table, the alkali metal group. It exists only in short-lived radioactive forms. Natural francium cannot be isolated in visible, weighable amounts, for only 24.5 grams (0.86 ounce) occur at...
Freon (trademark), any of several simple fluorinated aliphatic organic compounds that are used in commerce and industry. In addition to fluorine and carbon, Freons often contain hydrogen, chlorine, or bromine. Thus, Freons are types of chlorofluorocarbons...
fullerene any of a series of hollow carbon molecules that form either a closed cage (“buckyballs”) or a cylinder (carbon “nanotubes”). The first fullerene was discovered in 1985 by Sir Harold W. Kroto (one of the authors of this article) of the United Kingdom...
gadolinium Gd chemical element, a rare-earth metal of the lanthanide series of the periodic table. Gadolinium is a moderately ductile, moderately hard, silvery white metal that is fairly stable in air, although with time it tarnishes in air, forming a thin film...
Gahn, Johan Gottlieb Swedish mineralogist and crystallographer who discovered manganese in 1774. His failure to win fame may be related to the fact that he published little. He saved the notes, papers, and letters of his friend Carl Wilhelm Scheele, who discovered chlorine,...
gallium Ga chemical element, metal of main Group 13 (IIIa, or boron group) of the periodic table. It liquefies just above room temperature. Gallium was discovered (1875) by French chemist Paul-Émile Lecoq de Boisbaudran, who observed its principal spectral lines...
Gay-Lussac, Joseph-Louis French chemist and physicist who pioneered investigations into the behaviour of gases, established new techniques for analysis, and made notable advances in applied chemistry. Early career Gay-Lussac was the eldest son of a provincial lawyer and royal...
geochemical cycle developmental path followed by individual elements or groups of elements in the crustal and subcrustal zones of the Earth and on its surface. The concept of a geochemical cycle encompasses geochemical differentiation (i.e., the natural separation and...
germanium Ge a chemical element between silicon and tin in Group 14 (IVa) of the periodic table, a silvery-gray metalloid, intermediate in properties between the metals and the nonmetals. Although germanium was not discovered until 1886 by Clemens Winkler, a German...
gold Au chemical element, a dense, lustrous, yellow precious metal of Group 11 (Ib), Period 6, of the periodic table. Gold has several qualities that have made it exceptionally valuable throughout history. It is attractive in colour and brightness, durable...
graphene a two-dimensional form of crystalline carbon, either a single layer of carbon atoms forming a honeycomb (hexagonal) lattice or several coupled layers of this honeycomb structure. The word graphene, when used without specifying the form (e.g., bilayer...
graphite mineral consisting of carbon. Graphite has a layered structure that consists of rings of six carbon atoms arranged in widely spaced horizontal sheets. Graphite thus crystallizes in the hexagonal system, in contrast to the same element crystallizing in...
group in chemistry, a set of chemical elements in the same vertical column of the periodic table. The elements in a group have similarities in the electronic configuration of their atoms, and thus they exhibit somewhat related physical and chemical properties....
Guyton de Morveau, Louis Bernard French chemist who played a major part in the reform of chemical nomenclature. Lawyer to chemist The son of a lawyer, Guyton added the title de Morveau (from a family property) to his name after he became a lawyer and a public prosecutor in 1762. During...
hafnium Hf chemical element (atomic number 72), metal of Group 4 (IVb) of the periodic table. It is a ductile metal with a brilliant silvery lustre. The Dutch physicist Dirk Coster and the Hungarian Swedish chemist George Charles von Hevesy discovered (1923)...
halocarbon any chemical compound of the element carbon and one or more of the halogens (bromine, chlorine, fluorine, iodine); two important subclasses of halocarbons are the chlorocarbons, containing only carbon and chlorine, and the fluorocarbons, containing only...
halogen element any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). They were given the name halogen, from...
halon chemical compound formerly used in firefighting. A halon may be any of a group of organohalogen compounds containing bromine and fluorine and one or two carbons. The effectiveness of halons in extinguishing fires arises from their action in interrupting...
Hammond, John Hays U.S. mining engineer who helped develop gold mining in South Africa and California. In 1880 he was engaged by the U.S. Geological Survey for a study of the California goldfields; afterward, as a consulting engineer, he visited most of the countries of...
Hancock, Langley George Australian mining industrialist who unearthed some of the largest iron-ore reserves in the world, making him one of the nation’s richest citizens and financing his campaign to form a right-wing political party and to fight for Western Australian independence....
hard water water that contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous iron may also be present; oxidized to the ferric form, it appears as a reddish brown stain on washed fabrics and enameled surfaces. Water...
hassium Hs an artificially produced element belonging to the transuranium group, atomic number 108. It was synthesized and identified in 1984 by West German researchers at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung [GSI]) in...
Hatchett, Charles English manufacturer, chemist, and discoverer in 1801 of niobium, which he called columbium. Because of his expertise in analysis, Hatchett was frequently called on as a consultant. Mineral substances found in Australia (hatchettine or hatchettite) and...
heavy water D 2 O water composed of deuterium, the hydrogen isotope with a mass double that of ordinary hydrogen, and oxygen. (Ordinary water has a composition represented by H 2 O.) Thus, heavy water has a molecular weight of about 20 (the sum of twice the atomic...
helium He chemical element, inert gas of Group 18 (noble gases) of the periodic table. The second lightest element (only hydrogen is lighter), helium is a colourless, odourless, and tasteless gas that becomes liquid at −268.9 °C (−452 °F). The boiling and freezing...
heptachlor insecticide closely related to chlordane.
holmium Ho chemical element, a rare-earth metal of the lanthanide series of the periodic table. Holmium is a moderately hard, silvery white metal that is relatively stable in air. It readily reacts with diluted acids but does not react with either diluted or...
hydrate any compound containing water in the form of H 2 O molecules, usually, but not always, with a definite content of water by weight. The best-known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water....
hydrazine (N 2 H 4), one of a series of compounds called hydronitrogens and a powerful reducing agent. It is used in the synthesis of various pesticides, as a base for blowing agents that make the holes in foam rubber, and as a corrosion inhibitor in boilers....
hydride any of a class of chemical compounds in which hydrogen is combined with another element. Three basic types of hydrides—saline (ionic), metallic, and covalent—may be distinguished on the basis of type of chemical bond involved. A fourth type of hydride,...
hydrofluorocarbon HFC any of several organic compounds composed of hydrogen, fluorine, and carbon. HFCs are produced synthetically and are used primarily as refrigerants. They became widely used for this purpose beginning in the late 1980s, with the introduction of the...
hydrogen H a colourless, odourless, tasteless, flammable gaseous substance that is the simplest member of the family of chemical elements. The hydrogen atom has a nucleus consisting of a proton bearing one unit of positive electrical charge; an electron, bearing...
hydrogen chloride (HCl), a compound of the elements hydrogen and chlorine, a gas at room temperature and pressure. A solution of the gas in water is called hydrochloric acid. Hydrogen chloride may be formed by the direct combination of chlorine (Cl 2) gas and hydrogen...
hydrogen peroxide (H 2 O 2), a colourless liquid usually produced as aqueous solutions of various strengths, used principally for bleaching cotton and other textiles and wood pulp, in the manufacture of other chemicals, as a rocket propellant, and for cosmetic and medicinal...
hydrogen sulfide colourless, extremely poisonous, gaseous compound formed by sulfur with hydrogen (see sulfur).
hydrometeor any water or ice particles that have formed in the atmosphere or at the Earth’s surface as a result of condensation or sublimation. Water or ice particles blown from the ground into the atmosphere are also classed as hydrometeors. Some well-known hydrometeors...
ice solid substance produced by the freezing of water vapour or liquid water. At temperatures below 0 °C (32 °F), water vapour develops into frost at ground level and snowflakes (each of which consists of a single ice crystal) in clouds. Below the same temperature,...
indium In chemical element, rare metal of main Group 13 (IIIa, or boron group) of the periodic table. Indium has a brilliant silvery-white lustre. It was discovered (1863) by German chemists Ferdinand Reich and Hieronymus Theodor Richter while they were examining...
iodine I chemical element, a member of the halogen elements, or Group 17 (Group VIIa) of the periodic table. History In 1811 the French chemist Bernard Courtois obtained a violet vapour by heating seaweed ashes with sulfuric acid as a by-product of the manufacture...
iodoform a yellow, crystalline solid belonging to the family of organic halogen compounds, used as an antiseptic component of medications for minor skin diseases. First prepared in 1822, iodoform is manufactured by electrolysis of aqueous solutions containing...
iridium Ir chemical element, one of the platinum metals of Groups 8–10 (VIIIb), Periods 5 and 6, of the periodic table. It is very dense and rare and is used in platinum alloys. A precious, silver-white metal, iridium is hard and brittle, but it becomes ductile...
iridosmine mineral consisting of an alloy of iridium and a smaller proportion of osmium. It occurs in gold-bearing conglomerates, as at the Witwatersrand in South Africa, and in gold sands, as in California and Oregon, U.S. Because of their hardness and resistance...
iron Fe chemical element, metal of Group 8 (VIIIb) of the periodic table, the most used and cheapest metal. Occurrence, uses, and properties Iron makes up 5 percent of the Earth’s crust and is second in abundance to aluminum among the metals and fourth in...
isodrin chlorine-containing organic compound used as an insecticide; see aldrin.
isotope one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties. Every chemical element has one...
kamacite mineral consisting of iron alloyed with 5–7 percent nickel by weight and found in almost all meteorite s which contain nickel-iron metal. It has a body-centred cubic structure and is sometimes referred to as α iron, after one of the three temperature-dependent...
Kelly, William American ironmaster who invented the pneumatic process of steelmaking, in which air is blown through molten pig iron to oxidize and remove unwanted impurities. Also patented by Sir Henry Bessemer of Great Britain, this process produced the first inexpensive...
Klaus, Karl Karlovich Russian chemist (of German origin) credited with the discovery of ruthenium in 1844. Klaus was educated at Dorpat, where he became a pharmacist; later he taught chemistry and pharmacy at the universities of Dorpat and Kazan. Klaus was noted for his researches...
krypton Kr chemical element, rare gas of Group 18 (noble gases) of the periodic table, which forms relatively few chemical compounds. About three times heavier than air, krypton is colourless, odourless, tasteless, and monatomic. Although traces are present...
lanthanoid any of the series of 15 consecutive chemical element s in the periodic table from lanthanum to lutetium (atomic numbers 57–71). With scandium and yttrium, they make up the rare-earth metal s. Their atoms have similar configurations and similar physical...
lanthanoid contraction in chemistry, the steady decrease in the size of the atoms and ions of the rare earth elements with increasing atomic number from lanthanum (atomic number 57) through lutetium (atomic number 71). For each consecutive atom the nuclear charge is more positive...
lanthanum La chemical element, a rare-earth metal of Group 3 of the periodic table, that is the prototype of the lanthanide series of elements. Lanthanum is a ductile and malleable silvery white metal that is soft enough to be cut with a knife. It is the second...
Lavoisier, Antoine-Laurent prominent French chemist and leading figure in the 18th-century chemical revolution who developed an experimentally based theory of the chemical reactivity of oxygen and coauthored the modern system for naming chemical substances. Having also served...
lawrencium Lr synthetic chemical element, the 14th member of the actinoid series of the periodic table, atomic number 103. Not occurring in nature, lawrencium (probably as the isotope lawrencium-257) was first produced (1961) by chemists Albert Ghiorso, T. Sikkeland,...
lead Pb a soft, silvery white or grayish metal in Group 14 (IVa) of the periodic table. Lead is very malleable, ductile, and dense and is a poor conductor of electricity. Known in antiquity and believed by the alchemists to be the oldest of metals, lead is...
Lecoq de Boisbaudran, Paul-Émile French chemist who developed improved spectroscopic techniques for chemical analysis and discovered the elements gallium (1875), samarium (1880), and dysprosium (1886). In 1858 Lecoq de Boisbaudran began working in the family wine business, though he...
lewisite in chemical warfare, poison blister gas developed by the United States for use during World War I. Chemically, the substance is dichloro(2-chlorovinyl)arsine, a liquid whose vapour is highly toxic when inhaled or when in direct contact with the skin....
Linde, Carl Paul Gottfried von German engineer whose invention of a continuous process of liquefying gases in large quantities formed a basis for the modern technology of refrigeration and provided both impetus and means for conducting scientific research at low temperatures and very...
litharge one of two mineral forms of lead(II) oxide (PbO). It is found with the other form, massicot, as dull or greasy, very heavy, soft, red crusts in the oxidized zone of lead deposits, as at Cucamonga Peak and Fort Tejon, Calif., U.S., and near Hailey, Idaho,...
lithium Li chemical element of Group 1 (Ia) in the periodic table, the alkali metal group, lightest of the solid elements. The metal itself—which is soft, white, and lustrous—and several of its alloys and compounds are produced on an industrial scale. Occurrence...
livermorium Lv artificially produced transuranium element of atomic number 116. In 2000 scientists at the Joint Institute for Nuclear Research in Dubna, Russia, and the Lawrence Livermore National Laboratory in Livermore, California, announced the production of...
Loschmidt, Joseph German chemist who made advances in the study of aromatic hydrocarbons. The son of poor peasants, Loschmidt gained an education through the help of his village priest, and by 1839 he was a student at the German University in Prague. Moving to Vienna...
Lundeberg, Christian industrialist and politician who presided over the 1905 Swedish government, which negotiated an end to the Swedish-Norwegian union. A leading ironmaster, Lundeberg was active in industrial organizations and local government before entering the upper...
lutetium Lu chemical element, a rare-earth metal of the lanthanide series of the periodic table, that is the densest and the highest-melting rare-earth element and the last member of the lanthanide series. In its pure form, lutetium metal is silvery white and...
magnesium Mg chemical element, one of the alkaline-earth metals of Group 2 (IIa) of the periodic table, and the lightest structural metal. Its compounds are widely used in construction and medicine, and magnesium is one of the elements essential to all cellular...
manganese Mn chemical element, one of the silvery white, hard, brittle metals of Group 7 (VIIb) of the periodic table. It was recognized as an element in 1774 by the Swedish chemist Carl Wilhelm Scheele while working with the mineral pyrolusite and was isolated...
Marggraf, Andreas Sigismund German chemist whose discovery of beet sugar in 1747 led to the development of the modern sugar industry. Marggraf served as assistant (1735–38) to his father, the court apothecary at Berlin, and as director of the chemical laboratory of the German Academy...
Marignac, Jean-Charles-Galissard de Swiss chemist whose work with atomic weights suggested the possibility of isotopes and the packing fraction of nuclei and whose study of the rare-earth elements led to his discovery of ytterbium in 1878 and codiscovery of gadolinium in 1880. After studying...
massicot one of the two forms of lead oxide (PbO) that occurs as a mineral (the other form is litharge). Massicot forms by the oxidation of galena and other lead minerals as soft, yellow, earthy or scaly masses that are very dense. It has been found in significant...
McMillan, Edwin Mattison American nuclear physicist who shared the Nobel Prize for Chemistry in 1951 with Glenn T. Seaborg for his discovery of element 93, neptunium, the first element heavier than uranium, thus called a transuranium element. McMillan was educated at the California...
meitnerium Mt an artificially produced element belonging to the transuranium group, atomic number 109. It is predicted to have chemical properties resembling those of iridium. The element is named in honour of German physicist Lise Meitner. In 1982 West German...
Mendeleev, Dmitri Russian chemist who developed the periodic classification of the elements. Mendeleev found that, when all the known chemical element s were arranged in order of increasing atomic weight, the resulting table displayed a recurring pattern, or periodicity,...
mendelevium Md synthetic chemical element of the actinoid series of the periodic table, atomic number 101. It was the first element to be synthesized and discovered a few atoms at a time. Not occurring in nature, mendelevium (as the isotope mendelevium-256) was...
mercury Hg chemical element, liquid metal of Group 12 (IIb, or zinc group) of the periodic table. Properties, uses, and occurrence Mercury was known in Egypt and also probably in the East as early as 1500 bce. The name mercury originated in 6th-century alchemy,...
metal any of a class of substances characterized by high electrical and thermal conductivity as well as by malleability, ductility, and high reflectivity of light. Approximately three-quarters of all known chemical elements are metals. The most abundant varieties...
metalloid a chemical element with properties intermediate between those of typical metals and nonmetals. Usually considered under this classification are the chemical elements boron, silicon, germanium, arsenic, antimony, and tellurium. The rare elements polonium...
methoxychlor a colourless, crystalline organic halogen compound used as an insecticide. Methoxychlor is very similar to DDT but acts more rapidly, is less persistent, and does not accumulate in the fatty tissues of animals as does DDT. Methoxychlor is prepared by...
methyl bromide a colourless, nonflammable, highly toxic gas (readily liquefied) belonging to the family of organic halogen compounds. It is used as a fumigant against insects and rodents in food, tobacco, and nursery stock; smaller amounts are used in the preparation...
methyl chloride CH 3 Cl a colourless, flammable, toxic gas. Methyl chloride is primarily prepared by reaction of methanol with hydrogen chloride, although it also can be prepared by chlorination of methane. Annual production in the United States alone is in the hundreds...
methylene chloride a colourless, volatile, practically nonflammable liquid belonging to the family of organic halogen compounds. It is extensively used as a solvent, especially in paint-stripping formulations. Methylene chloride is commercially produced along with methyl...
Meyer, Lothar German chemist who, independently of Dmitry Mendeleyev, developed a periodic classification of the chemical elements. Though originally educated as a physician, he was chiefly interested in chemistry and physics. In 1859 Meyer began his career as a science...
misch metal alloy consisting of about 50 percent cerium, 25 percent lanthanum, 15 percent neodymium, and 10 percent other rare-earth metals and iron. Misch metal has been produced on a relatively large scale since the early 1900s as the primary commercial form of...
Moissan, Henri French chemist who received the 1906 Nobel Prize for Chemistry for the isolation of the element fluorine and the development of the Moissan electric furnace. After attending the Museum of Natural History and the School of Pharmacy in Paris, Moissan became...
molybdenum Mo chemical element, silver-gray refractory metal of Group 6 (VIb) of the periodic table, used to impart superior strength to steel and other alloys at high temperature. The Swedish chemist Carl Wilhelm Scheele had demonstrated (c. 1778) that the mineral...