Is boron a metal or nonmetal? | Reference.com Is boron a metal or nonmetal? A: Quick Answer Boron is neither a metal nor a nonmetal; instead, it is classified as a metalloid or a semimetal. Boron is the chemical element with the symbol B and atomic number 5. Its molecular weight is 10.81 grams per mole, and its melting point is 2076 degrees Celsius. Full Answer Crystal boron is a dark substance with a hardness rivaling that of diamond. As a metalloid, boron's physical and chemical properties are between those of metals and nonmetals. It behaves as a nonmetal in reaction with sodium and a metal when combined with fluorine. Other chemical elements commonly classified as metalloids include silicon, germanium, arsenic, antimony and tellurium. What does metalloid mean?

This page provides all possible meanings and translations of the word metalloid Princeton's WordNet(0.00 / 0 votes)Rate this definition: metalloid(adj) of or being a nonmetallic element that has some of the properties of metal "arsenic is a metalloid element" Wiktionary(5.00 / 1 vote)Rate this definition: metalloid(Noun) An element, such as silicon or germanium, intermediate in properties between that of a metal and a nonmetal; especially one that exhibits the external characteristics of a metal, but behaves chemically more as a nonmetal. Webster Dictionary(0.00 / 0 votes)Rate this definition: Metalloid(noun) formerly, the metallic base of a fixed alkali, or alkaline earth; -- applied by Sir H.

Davy to sodium, potassium, and some other metallic substances whose metallic character was supposed to be not well defined Metalloid(noun) now, one of several elementary substances which in the free state are unlike metals, and whose compounds possess or produce acid, rather than basic, properties; a nonmetal; as, boron, carbon, phosphorus, nitrogen, oxygen, sulphur, chlorine, bromine, etc., are metalloids Metalloid(adj) having the properties of a nonmetal; nonmetallic; acid; negative Origin: [L. metallum metal + -oid: cf. F. mtallode.] Freebase(1.00 / 1 vote)Rate this definition: Metalloid A metalloid is a chemical element with properties that are in between or a mixture of those of metals and nonmetals, and which is considered to be difficult to classify unambiguously as either a metal or a nonmetal. There is no standard definition of a metalloid nor is there agreement as to which elements are appropriately classified as such. Despite this lack of specificity the term continues to be used in the chemistry literature.

The six elements commonly recognised as metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Other elements less commonly recognised as metalloids include carbon, aluminium, selenium, polonium and astatine. On a standard periodic table all of these elements can be found in or near a diagonal region of the p-block, having its main axis anchored by boron at one end and astatine at the other. Some periodic tables include a dividing line between metals and nonmetals and it is generally the elements adjacent to this line or, less frequently, one or more of the elements adjacent to those elements, which are identified as metalloids. Physically, metalloids usually have a metallic appearance but they are brittle and only fair conductors of electricity; chemically, they mostly behave as nonmetals. They can, however, form alloys with metals. Ordinarily, most of the other physical and chemical properties of metalloids are intermediate in nature. Numerology The numerical value of metalloid in Chaldean Numerology is: 5 Pythagorean Numerology Metalloid | Define Metalloid at Dictionary.com metalloid a nonmetal that in combination with a metal forms an alloy. 2.

an element that has both metallic and nonmetallic properties, as arsenic, silicon, or boron. adjective of or relating to a metalloid. 4. resembling both a metal and a nonmetal. Origin of metalloid British Dictionary definitions for metalloid Expand noun 1. a nonmetallic element, such as arsenic or silicon, that has some of the properties of a metal adjective of or being a metalloid 3. Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 metalloid (mět'l-oid') An element that is not a metal but that has some properties of metals. Arsenic, for example, is a metalloid that has the visual appearance of a metal, but is a poor conductor of electricity; metalloids are generally semiconductors.

The elements classified as metalloids are boron, silicon, germanium, arsenic, antimony, tellurium, and polonium. Metalloids can be viewed as a diagonal section on the Period Table, separating metals from nonmetals. A nonmetallic element, such as carbon, that can form alloys with metals. The American Heritage® Science Dictionary Copyright © 2002. Published by Houghton Mifflin. All rights reserved. Chemistry - 6 | Britannica.com Chemistry the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed... Browse Subcategories: (54) Displaying 401 - 500 of 800 results Lee, Yuan T. Taiwanese-American chemist who, with Dudley R. Herschbach and John C. Polanyi, received the Nobel Prize for Chemistry in 1986 for his role in the development of chemical-reaction dynamics. Lee was educated in Taiwan and at the University of California... Lehn, Jean-Marie French chemist who, together with Charles J. Pedersen and Donald J.

Cram, was awarded the Nobel Prize for Chemistry in 1987 for his contribution to the laboratory synthesis of molecules that mimic the vital chemical functions of molecules in living organisms.... Leloir, Luis Federico Argentine biochemist who won the Nobel Prize for Chemistry in 1970 for his investigations of the processes by which carbohydrates are converted into energy in the body. After serving as an assistant at the Institute of Physiology, University of Buenos... Leslie, Sir John Scottish physicist and mathematician who first created artificial ice. In 1802 Leslie’s explanation of capillary action was the first that is consistent with present-day theory. Two years later he published An Experimental Inquiry into the Nature and... Levene, Phoebus Russian-born American chemist and pioneer in the study of nucleic acids. On receiving his M.D. degree from the St. Petersburg Imperial Medical Academy in 1891, Levene fled from Russian anti-Semitism and settled in New York City. While practicing medicine... Levitt, Michael American British Israeli chemist who was awarded the 2013 Nobel Prize for Chemistry for developing accurate computer models of chemical reactions that were able to use features of both classical physics and quantum mechanics.

He shared the prize with... Lewis, Gilbert N. American physical chemist best known for his contributions to chemical thermodynamics, the electron-pair model of the covalent bond, the electronic theory of acids and bases, the separation and study of deuterium and its compounds, and his work on phosphorescence... Lewis theory generalization concerning acids and bases introduced in 1923 by the U.S. chemist Gilbert N. Lewis, in which an acid is regarded as any compound which, in a chemical reaction, is able to attach itself to an unshared pair of electrons in another molecule.... Libavius, Andreas German chemist, physician, and alchemist who made important chemical discoveries but is most noted as the author of the first modern chemistry textbook. Libavius was professor of history and poetry at the University of Jena from 1586 to 1591 and then... Libby, Willard Frank American chemist whose technique of carbon-14 (or radiocarbon) dating provided an extremely valuable tool for archaeologists, anthropologists, and earth scientists. For this development he was honoured with the Nobel Prize for Chemistry in 1960. Libby,...

Liebig, Justus, Freiherr von German chemist who made significant contributions to the analysis of organic compounds, the organization of laboratory-based chemistry education, and the application of chemistry to biology (biochemistry) and agriculture. Training and early career Liebig... ligand in chemistry, any atom or molecule attached to a central atom, usually a metallic element, in a coordination or complex compound. The atoms and molecules used as ligands are almost always those that are capable of functioning as the electron-pair donor... ligand field theory in chemistry, one of several theories that describe the electronic structure of coordination or complex compounds, notably transition metal complexes, which consist of a central metal atom surrounded by a group of electron-rich atoms or molecules called... Lindahl, Tomas Swedish biochemist known for his discovery of base excision repair, a major mechanism of DNA repair, by which cells maintain their genetic integrity. Base excision repair corrects damage sustained by individual DNA bases (adenine, cytosine, guanine,... lipid any of a diverse group of organic compounds including fats, oils, hormones, and certain components of membranes that are grouped together because they do not interact appreciably with water.

One type of lipid, the triglycerides, is sequestered as fat... Lipmann, Fritz Albert German-born American biochemist, who received (with Sir Hans Krebs) the 1953 Nobel Prize for Physiology or Medicine for the discovery of coenzyme A, an important catalytic substance involved in the cellular conversion of food into energy. Lipmann earned... Lipscomb, William Nunn, Jr. American physical chemist who won the Nobel Prize for Chemistry in 1976 for his research on the structure and bonding of boron compounds and the general nature of chemical bonding. Lipscomb graduated from the University of Kentucky in 1941 and earned... 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... Loewi, Otto German-born American physician and pharmacologist who, with Sir Henry Dale, received the Nobel Prize for Physiology or Medicine in 1936 for their discoveries relating to the chemical transmission of nerve impulses. After Loewi graduated in medicine (1896)... Lomonosov, Mikhail Russian poet, scientist, and grammarian who is often considered the first great Russian linguistic reformer. He also made substantial contributions to the natural sciences, reorganized the St. Petersburg Imperial Academy of Sciences, established in Moscow... London, Fritz Wolfgang German American physicist who did pioneering work in quantum chemistry and on macroscopic quantum phenomena of superconductivity and superfluidity. London received his doctorate in philosophy (1921) from the University of Munich before switching in 1925... 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... Lovelock, James English chemist, medical doctor, scientific instrument developer, and author best known for the creation and promulgation of the Gaia hypothesis, an idea rooted in the notion that all life on Earth is part of an entity that regulates Earth’s surficial... Lucite trademark name of polymethyl methacrylate, a synthetic organic compound of high molecular weight made by combination of many simple molecules of the ester methyl methacrylate (monomer) into long chains (polymer); this process (polymerization) may be... 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...

Lynen, Feodor German biochemist who, for his research on the metabolism of cholesterol and fatty acids, was a corecipient (with Konrad Bloch) of the 1964 Nobel Prize for Physiology or Medicine. Lynen was trained at the University of Munich. After several years as... MacDiarmid, Alan G. New Zealand-born American chemist who, with Alan J. Heeger and Shirakawa Hideki, was awarded the Nobel Prize for Chemistry in 2000 for their discovery that certain plastics can be chemically modified to conduct electricity almost as readily as metals.... Macintosh, Charles Scottish chemist, best known for his invention in 1823 of a method for making waterproof garments by using rubber dissolved in coal-tar naphtha for cementing two pieces of cloth together. The mackintosh garment was named for him. In 1823, while trying... MacKinnon, Roderick American doctor, corecipient of the Nobel Prize for Chemistry in 2003 for his pioneering research on ion channels in cell membranes. He shared the award with Peter Agre, also of the United States. MacKinnon earned an M.D.

degree from Tufts University... macromolecule any very large molecule, usually with a diameter ranging from about 100 to 10,000 angstroms (10 - 5 to 10 - 3 millimetre). The molecule is the smallest unit of the substance that retains its characteristic properties; the macromolecule is such a unit... 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... Marcus, Rudolph A. Canadian-born American chemist, winner of the 1992 Nobel Prize for Chemistry for his work on the theory of electron-transfer reactions in chemical systems. The Marcus theory shed light on diverse and fundamental phenomena such as photosynthesis, cell...

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... Mark, Herman Francis Austrian American chemist who, although not the world’s first polymer chemist, was known as the father of polymer science because of his many contributions to polymer science education and research. In 1913 Mark decided to fulfill his military obligation...

Markovnikov rule in organic chemistry, a generalization, formulated by Vladimir Vasilyevich Markovnikov in 1869, stating that in addition reactions to unsymmetrical alkenes, the electron-rich component of the reagent adds to the carbon atom with fewer hydrogen atoms... Markovnikov, Vladimir Vasilyevich Russian organic chemist who contributed to structural theory and to the understanding of the ionic addition (Markovnikov addition) of hydrogen halides to the carbon-carbon double bond of alkenes. After studying at the universities of Kazan and St. Petersburg,... Martin, A. J. P. British biochemist who was awarded (with R.L.M. Synge) the Nobel Prize for Chemistry in 1952 for development of paper partition chromatography, a quick and economical analytical technique permitting extensive advances in chemical, medical, and biological... Marvel, Carl Shipp American chemist whose early research was in classic organic chemistry but who is best known for his contributions to polymer chemistry. After receiving bachelor’s and master’s degrees in chemistry (both in 1915) from Illinois Wesleyan University in...

Mayow, John English chemist and physiologist who, about a hundred years before Joseph Priestley and Antoine-Laurent Lavoisier, identified spiritus nitroaereus (oxygen) as a distinct atmospheric entity. Though a doctor of law from the University of Oxford (1670),... McCrone, Walter C., Jr. American scientist who used chemical microscopy to debunk historical myths and forgeries. By examining samples of hair, he ascertained that Napoleon Bonaparte did not die from poisoning but that Ludwig van Beethoven did contract lead poisoning. McCrone... McIntire, Ray U.S. chemical engineer who inadvertently created what became known as Styrofoam while working for the Dow Chemical Co., where he was attempting to develop a rubberlike polymer to be used as a flexible insulator (b. Aug. 24, 1918--d. Feb. 2, 1996). 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... Mendel, Lafayette Benedict American biochemist whose discoveries concerning the value of vitamins and proteins helped establish modern concepts of nutrition. A professor of physiological chemistry at Yale from 1903 to 1935, he worked with the American biochemist Thomas Osborne... 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...

Menten, Maud Leonora Canadian biochemist and organic chemist best known for her work on enzyme kinetics. She also made important discoveries contributing to the science of histochemistry (the staining of cells with chemicals such as dyes, enabling microscopic visualization... 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,... Merrifield, Bruce American biochemist and educator, who in 1984 received the Nobel Prize for Chemistry for his development of a simple and ingenious method for synthesizing chains of amino acids, or polypeptides, in any predetermined order. Merrifield graduated from the... 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...

metal carbonyl any coordination or complex compound consisting of a heavy metal such as nickel, cobalt, or iron surrounded by carbonyl (CO) groups. Some common metal carbonyls include: tetracarbonylnickel Ni(CO) 4, pentacarbonyliron Fe(CO) 5, and octacarbonyldicobalt... 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... 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... Meyer, Viktor German chemist who contributed greatly to knowledge of both organic and inorganic chemistry. Meyer studied under the analytic chemist Robert Bunsen, the organic chemist Emil Erlenmeyer, and the physicist Gustav Kirchhoff at the University of Heidelberg,...

Meyerhof, Otto German biochemist and corecipient, with Archibald V. Hill, of the 1922 Nobel Prize for Physiology or Medicine for research on the chemical reactions of metabolism in muscle. His work on the glycogen-lactic acid cycle remains a basic contribution to the... Meyerson, Émile Polish-born French chemist and philosopher of science whose concepts of rational understanding based on realism and causalism were popular among scientific theorists in the 1930s. Educated in classical science and chemistry under Robert Wilhelm Bunsen... Michaelis–Menten hypothesis a general explanation of the velocity and gross mechanism of enzyme-catalyzed reactions. First stated in 1913, the hypothesis assumes the rapid, reversible formation of a complex between an enzyme and its substrate (the substance upon which it acts to... Michel, Hartmut German biochemist who, along with Johann Deisenhofer and Robert Huber, received the Nobel Prize for Chemistry in 1988 for their determination of the structure of certain proteins that are essential for photosynthesis. Michel earned his doctorate from... Midgley, Thomas, Jr.

American engineer and chemist who discovered the effectiveness of tetraethyl lead as an antiknock additive for gasoline. He also found that dichlorodifluoromethane (a type of fluorocarbon commercialized under the trade name Freon -12) could be used as... Miller, Stanley Lloyd American chemist who designed the first experiment to produce organic molecules from some of the inorganic components of the Earth’s prebiotic atmosphere. Miller’s procedure (which was co-designed by Harold Urey and is known as the Miller-Urey experiment)... Mills, Victor American chemical engineer who, while working for the Procter & Gamble Co., revolutionized child care with the invention of the disposable diaper; he began work on that product in the 1950s, using his grandchildren as test subjects (b. 1897--d. Nov.... Mitchell, Peter Dennis British chemist who won the 1978 Nobel Prize for Chemistry for helping to clarify how ADP (adenosine diphosphate) is converted into the energy-carrying compound ATP (adenosine triphosphate) in the mitochondria of living cells. Mitchell received his Ph.D....

Mitscherlich, Eilhardt German chemist who promulgated the theory of isomorphism, a relationship between crystalline structure and chemical composition. From 1818 to 1820 Mitscherlich worked in the Berlin laboratory of the German botanist Heinrich F. Link, where he first undertook... Modrich, Paul American biochemist who discovered mismatch repair, a mechanism by which cells detect and correct errors that are introduced into DNA during DNA replication and cell division. Modrich was among the first to show that a common form of inherited colorectal... Moerner, W.E. American chemist who won the 2014 Nobel Prize for Chemistry for his work with single- molecule spectroscopy, which paved the way for later work in single-molecule microscopy by American physicist Eric Betzig. Moerner and Betzig shared the prize with... Mohr, Karl Friedrich German chemist who invented such laboratory apparatus as the pinchcock, cork borer, and Mohr’s balance. The leading scientific pharmacist of his time in Germany, he improved many analytical processes and was one of the first to enunciate the doctrine...

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... molecular weight mass of a molecule of a substance, based on 12 as the atomic weight of carbon -12. It is calculated in practice by summing the atomic weights of the atoms making up the substance’s molecular formula. The molecular weight of a hydrogen molecule (chemical... molecule a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance. The division of a sample of a substance into progressively smaller... Molina, Mario Mexican-born American chemist who was jointly awarded the 1995 Nobel Prize for Chemistry, along with chemists F. Sherwood Rowland and Paul Crutzen, for research in the 1970s concerning the decomposition of the ozonosphere, which shields Earth from dangerous...

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... Mond, Ludwig German-born British chemist and industrialist who improved the Solvay alkali process and devised a process for the extraction of nickel. The son of a wealthy Jewish family, Mond studied chemistry at Marburg and Heidelberg, entered the chemical industry,... Monod, Jacques French biochemist who, with François Jacob, did much to elucidate how genes regulate cell metabolism by directing the biosynthesis of enzymes. The pair shared, along with André Lwoff, the Nobel Prize for Physiology or Medicine in 1965. In 1961 Jacob... monomer a molecule of any of a class of compounds, mostly organic, that can react with other molecules to form very large molecules, or polymers. The essential feature of a monomer is polyfunctionality, the capacity to form chemical bonds to at least two other... Moore, Stanford American biochemist, who, with Christian B.

Anfinsen and William H. Stein, received the 1972 Nobel Prize for Chemistry for their research on the molecular structures of proteins. Moore received his Ph.D. degree from the University of Wisconsin in 1938... Morley, Edward Williams American chemist who is best known for his collaboration with the physicist A.A. Michelson in an attempt to measure the relative motion of the Earth through a hypothetical ether. Morley graduated from Williams College in 1860 and then pursued both scientific... Mosander, Carl Gustaf Swedish chemist whose work revealed the existence of numerous rare-earth elements with closely similar chemical properties. In 1826 Mosander was placed in charge of the chemical laboratory of the Caroline Medical Institute, Stockholm, and in 1832 became... moscovium Mc artificially produced transuranium element of atomic number 115. In 2010 scientists at the Joint Institute for Nuclear Research in Dubna, Russia, and at the Lawrence Berkeley National Laboratory in Berkeley, California, U.S., announced the production...

Moseley, Henry English physicist who experimentally demonstrated that the major properties of an element are determined by the atomic number, not by the atomic weight, and firmly established the relationship between atomic number and the charge of the atomic nucleus.... Müller, Paul Hermann Swiss chemist who received the Nobel Prize for Physiology or Medicine in 1948 for discovering the potent toxic effects on insects of DDT. With its chemical derivatives, DDT became the most widely used insecticide for more than 20 years and was a major... Mulliken, Robert Sanderson American chemist and physicist who received the 1966 Nobel Prize for Chemistry for “fundamental work concerning chemical bonds and the electronic structure of molecules.” A graduate of the Massachusetts Institute of Technology, Mulliken worked, during... Mullis, Kary B. American biochemist, cowinner of the 1993 Nobel Prize for Chemistry for his invention of the polymerase chain reaction (PCR), a simple technique that allows a specific stretch of DNA to be copied billions of times in a few hours. After receiving a doctorate...

multiple proportions, law of statement that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers. For example, there are five distinct oxides of nitrogen,... Murad, Ferid American pharmacologist, who, along with Robert F. Furchgott and Louis J. Ignarro, was co-awarded the 1998 Nobel Prize in Physiology or Medicine for the discovery that nitric oxide (NO) acts as a signaling molecule in the cardiovascular system. Their... native element any of a number of chemical elements that may occur in nature uncombined with other elements. The elements that occur as atmospheric gasses are excluded. Native elements name colour lustre Mohs hardness specific gravity habit or form allemontite tin-white;... Natta, Giulio Italian chemist who contributed to the development of high polymers useful in the manufacture of films, plastics, fibres, and synthetic rubber. Along with Karl Ziegler of Germany, he was honoured in 1963 with the Nobel Prize for Chemistry for the development...

Needham, Joseph English biochemist, embryologist, and historian of science who wrote and edited the landmark history Science and Civilisation in China, a comprehensive study of Chinese scientific development. The son of a physician, Needham earned a doctoral degree... Nef, John Ulric American chemist whose studies demonstrated that carbon can have a valence (i.e., affinity for electrons) of two as well as a valence of four, thus greatly advancing the understanding of theoretical organic chemistry. Brought to the United States by... Negishi Ei-ichi Japanese chemist who was awarded the 2010 Nobel Prize for Chemistry for his work in using palladium as a catalyst in producing organic molecules. He shared the prize with fellow Japanese chemist Suzuki Akira and American chemist Richard F. Heck. Negishi... neodymium Nd chemical element, a rare-earth metal of the lanthanide series of the periodic table. Neodymium is a ductile and malleable silvery white metal. It oxidizes readily in air to form an oxide, Nd 2 O 3, which easily spalls, exposing the metal to further...

neon Ne chemical element, inert gas of Group 18 (noble gases) of the periodic table, used in electric signs and fluorescent lamps. Colourless, odourless, tasteless, and lighter than air, neon gas occurs in minute quantities in Earth’s atmosphere and trapped... neptunium Np radioactive chemical element of the actinoid series of the periodic table that was the first transuranium element to be artificially produced, atomic number 93. Though traces of neptunium have subsequently been found in nature, where it is not primeval... neurotransmitter any of a group of chemical agents released by neurons (nerve cells) to stimulate neighbouring neurons, thus allowing impulses to be passed from one cell to the next throughout the nervous system. The site where neurons meet is called the synapse and... Newlands, John English chemist whose “law of octaves ” noted a pattern in the atomic structure of elements with similar chemical properties and contributed in a significant way to the development of the periodic law. Newlands studied at the Royal College of Chemistry,... Nicholson, William English chemist, discoverer of the electrolysis of water, which has become a basic process in both chemical research and industry.

Nicholson was at various times a hydraulic engineer, inventor, translator, and scientific publicist. He invented a hydrometer... nickel Ni chemical element, ferromagnetic metal of Group 10 (VIIIb) of the periodic table, markedly resistant to oxidation and corrosion. Properties, occurrence, and uses Silvery white, tough, and harder than iron, nickel is widely familiar because of its use... nickel–iron very rare native alloy of nickel and iron that contains between 24 and 77 percent nickel. It occurs in the gold washings of the Gorge River, N.Z.; in the platinum sands of the Bobrovka River, Urals; and in the gold dredgings of the Fraser River, B.C.... Metalloids | Elements4Kids Elements4Kids Another Palmer Way GATE Academy Creation Hey there! Thanks for dropping by Elements4Kids! Take a look around and grab the RSS feed to stay updated. See you around! Metalloid From Wikipedia, the free encyclopedia A metalloid is a chemical element with properties that are in-between or a mixture of those of metals and nonmetals, and which is considered to be difficult to classify unambiguously as either a metal or a nonmetal.

There is no standard definition of a metalloid nor is there agreement as to which elements are appropriately classified as such. Despite this lack of specificity the term continues to be used in the chemistry literature. The six elements commonly recognized as metalloids are boron , silicon , germanium , arsenic , antimony and tellurium . They are metallic-looking brittle solids, with intermediate to relatively good electrical conductivities, and each having the electronic band structure of either a semiconductor or a semimetal . Chemically, they mostly behave as (weak) nonmetals, have intermediate ionization energy and electronegativity values, and form amphoteric or weakly acidic oxides. Being too brittle to have any structural uses, the metalloids and their compounds instead find common use in glasses, alloys and semiconductors. The electrical properties of silicon and germanium, in particular, enabled the establishment of the semiconductor industry in the 1950s and the development of solid state electronics from the early 60s onwards. [2] [3] Other elements less commonly recognized as metalloids include carbon , aluminium , selenium , polonium and astatine .

On a standard periodic table these elements, as well as the elements commonly recognized as metalloids, occur in or near a diagonal region of the p-block , having its main axis anchored by boron at one end and astatine at the other. Some periodic tables include a dividing line between metals and nonmetals and it is generally the elements adjacent to this line or, less frequently, one or more of the elements adjacent to those elements, which are identified as metalloids. The term metalloid was first popularly used to refer to nonmetals. Its more recent meaning as a category of elements with intermediate or hybrid properties did not become widespread until the period 1940–1960. Metalloids are sometimes called semimetals, a practice which has been discouraged. This is because the term semimetal has a different meaning in physics, one which more specifically refers to the electronic band structure of a substance rather than the overall classification of a chemical element. Chemical properties Metalloids generally behave chemically as (weak) nonmetals, have intermediate ionization energies and electronegativities, and have amphoteric or weakly acidic oxides. They can also form alloys with metals.

Relevant properties—general, specific and descriptive—are set out in the following table: Property Metalloid | Word Metalloid at Open Dictionary of English by LearnThat Foundation Arsenic is a metalloid element As a metalloid, arsenic is a semiconductor, like silicon. Arsenic is an element (atomic number 33) classed as a semi-metal or metalloid. Despite its metallic appearance, it is not considered a metal, but a metalloid. The helmets were especially dramatic, molded of a dull-rose metalloid, with black fleurettes for cheek-pieces. Silicon, atomic number of 14, is a semi-metallic or metalloid, because it has several of the metallic characteristics. The headbands of men glittered, their tunics were of shimmering metalloid mesh, colorful trousers banded with gold went into soft half-boots. Unconcerned by the shifting tide of traffic advancing toward him across the blackened beach of this urban nightmare, he watched the luminous sun melt into the metalloid... Purser Hardy Dickens heard only the incessant tapping of metalloid bodies against metalloid walls, a reminder of the endless droning of days of his last hundred...

Franklinite is a black vitreo-metalloid substance, found in New It is a notoriously poisonous metalloid and hae many different form. It is a notoriously poisonous metalloid and has many different form. It contains no garnet or amphibole, but metalloid diallage disseminated in the mass. The element Antimony is a solid metalloid that belongs to the group called Pnictogen. Boron is an abundant metalloid (a small class of elements that are sort of metals and sort of not). I found no traces of this grey copper: it is probably the metalloid diallage that has given the Cerro de The 1st and 2nd generation photovoltaic cells require different forms of silicon, rare transition metals and metalloid elements. There is nearly 1,100 pounds of the notoriously poisonous metalloid arsenic in the site threatening to contaminate the groundwater. Texas has unlimited supply of Germanium. using Germanium in solar has a 40\% efficiency, more than any other combination of Minerals or metalloid. The serpentine is sometimes of an esquillous, sometimes of a conchoidal fracture: this was the first time I had found metalloid diallage within the tropics.

Little is known about antimony's toxicity, in part because the metalloid element is usually found at low, parts-per-billion concentrations in natural environments. There a guide told us how the semi-conductor metalloid is widely used in manufacturing top-notch optical fiber, infrared devices and above all, solar energy panels. BOC could churn out a jackhammer riff with the best of them, but it was also the lyrical content of their songs that set them apart from their 1970s metalloid competitors. The MEP is also aware that, over the past year, there have been 12 incidents of heavy metal and metalloid pollution in Dongchuan, a district of the south-western city of... I found no traces of this grey copper: it is probably the metalloid diallage that has given the Cerro de Guanabacoa the reputation of riches in gold and silver which it... For this reason Lombroso calls the occasional criminals "criminaloids," in order to show precisely that they have a distinctly abnormal constitution, though in a less degree... Specialty chemicals group LANXESS has now developed a product that can reliably remove this toxic metalloid from drinking water: Lewatit FO36 is an innovative hybrid...

A fist-pumper that proves Dave Grohl’s got plenty of throat-shredding screams, ridiculously catchy choruses and loud-quiet-loud metalloid riffs left in his quiver. Germanium is a metalloid. This was brought about by the increasing acceptance of allopathy) of the day that included bloodletting and high-dose injections of metal and metalloid compounds... Metalloids In Depth Tutorials and Information Metalloids concept The term “metalloid” may sound like a reference to a heavy-metal music fan, but in fact it describes a small collection of elements on the right-hand side of the periodic table. Forming a diagonal between boron and astatine, which lies four rows down and four columns to the right of boron, the metalloids are six elements that display qualities of both metals and nonmetals. (Some classifications include boron and astatine as well, but in this topic, they are treated as a nonmetal and a halogen respectively.) Of these six—silicon, germanium, arsenic, antimony, tellurium, and polonium—only a few are household names.

People know that arsenic is poison, and they have some general sense that silicon is important in surgical implants. But most people do not know that silicon, also the principal material in sand and glass, is the second-most plentiful element on Earth. Without silicon, from which computer chips are made, our computer-based society simply could not exist. How it works Families and “Orphans” Most elements fit into some sort of “family” grouping: the alkali metals, the alkaline earth metals, transition metals, lanthanides, actinides, halogens, and noble gases. These seven families, five metallic and two nonmetallic, account for 91 of 112 elements on the periodic table. The “orphan” elements, or those not readily classifiable within a family, occupy groups 3 through 6 on the North American version of the periodic table, which only numbers the “tall” columns. Twenty elements, occupying a rectangle that stretches across four groups or columns, and five periods or rows, are “orphans.” (This is in addition to hydrogen, on Period 1, Group 1.) These are best classified, not by family, but by cross-family characteristics that unite large groups of elements.

These cross-family groupings can be likened to nations: on one level, a person identifies with his or her family (“I’m a Smith”); but on another level, a person has a national identity (“I’m an American.”) Likewise gold, for instance, is both a member of the transition metals family, and of the larger metals grouping. The “orphan” elements, because they have no family, are best identified with characteristics that unite a large body of elements. (For this reason, the “orphan” metals are discussed in the Metals essay, and the “orphan” nonmetals in the Nonmetals essay.) Between Metals and nonmetals Of the twenty “orphan” elements in groups 3 through 6, seven are metals and seven nonmetals. Between them runs a diagonal, comprising the six metalloids. (As noted earlier, boron is sometimes considered a metalloid, but in this topic, it is discussed in the Nonmetals essay, while asta-tine—also sometimes grouped with the metalloids—is treated in the Halogens essay.) What is a metalloid? The best way to answer that question is by evaluating the differences between a metal and a nonmetal.

On the periodic table, metals fill the left, center, and part of the right-hand side of the Without silicon, from which computer chips are made, our computer-based society simply could not exist. Here, a worker holds a silicon wafer with integrated circuits. chart, as well as the two rows—corresponding to the lanthanides and actinides—placed separately at the bottom. Thus it should not come as a surprise that most elements (87, in fact) are metals. Metals are lustrous or shiny in appearance, and ductile, meaning that they can be molded into different shapes without breaking. They are excellent conductors of heat and electricity, and tend to form positive ions by losing electrons. Nonmetals, which occupy the upper right-hand side of the periodic table, include the noble gases, halogens, and the seven “orphan” elements alluded to above. With the addition of hydrogen (which, as noted, is covered in a separate essay), they comprise 19 elements. Whereas all metals are solids, except for mercury—a liquid at room temperature—the nonmetals are a collection o gases, solids, and one other liquid, bromine.

(No surprisingly, all gaseous elements are nonmetals. As their name suggests, nonmetals are opposit to metals in most regards: dull in appearance they are not particularly ductile or malleable With the exception of carbon, they are poor con ductors of heat and electricity, and tend to gai electrons to form negative ions. Survey of The Metalloids The metalloids can thus be defined as those elements which exhibit characteristics of both metals and nonmetals. They are all solids, but not lustrous, and conduct heat and electricity moderately well. The six metalloids treated here are listed below, with the atomic number and chemical symbol of each. • 14. Silicon (Si) • 52. Tellurium (Te) • 84. Polonium (Po) Silicon is the second most abundant element on Earth, comprising 25.7% of the planet’s known elemental mass. Together with oxygen, it accounts for nearly three-quarters of the known total.

(The planet’s core is probably composed largely of iron, with significant deposits of uranium and other metals between the crust and the core, but geologists can only make educated guesses as to the elemental composition beneath the crust.) The metalloids in history By far the most important of the metalloids, silicon has been in use as a compound for centuries, but was only isolated in the early nineteenth century. Arsenic and antimony were like-wise known from ancient times, and both attracted the attention of alchemists—medieval mystics, in many regards the forerunners of chemists, who believed it was possible to change plain metals into gold. Traces of the alchemical mindset remained a part of European science as late as the mid-eighteenth century, a tendency exemplified by the fact that tellurium, discovered around that time, was believed to be “unripe gold.” On the other hand, the discovery of germanium more than a century later—following predictions of its existence based on the periodic table—reflected a much greater degree of scientific rigor. Finally, the isolation of polonium, known for its radioactivity, was evidence of an even more advanced stage of development in chemistry and science as a whole.

Real-Life Applications Silicon Swedish chemist Jons Berzelius (1779-1848) discovered silicon in 1823, but humans had been using the element—in the form of compounds known as silicates—for thousands of years. Indeed, silicon may have been one of the first elements formed, many millions of years before life appeared on this planet. Geologists believe that the Earth was once composed primarily of molten iron, oxygen, silicon, and aluminum, still the predominant elements in the planet’s crust. Because iron has a greater atomic mass, it settled toward the center, while the more lightweight elements rose to the surface. Silicon is found in everything from the Sun and other stars, as well as meteorites, to plants and animal bones. Many hundreds of minerals on Earth contain silicon and oxygen in various forms: for instance, silicon and oxygen form silica (SiO2), commonly known as sand. This sand is mixed with lime and soda (sodium carbonate), as well other substances, to make glass. The purest varieties of silica form quartz, known for its clear crystals, while impure quartz forms crystals of semiprecious gems such as amethyst, opal, and agate.

compounds: silicates and silicones. Silicon is directly below carbon on the periodic table, and the elements in that group (which includes germanium, selenium, and lead) are sometimes called the “carbon family.” Like carbon, silicon forms a huge array of compounds, because it has four electrons to share in chemical bonding, and thus can form long strings of atoms. Because silicon atoms are much larger than carbon atoms, however, not as many other atoms can get close to silicon. Thus the number of possible compounds involving sil-icon—though still quite impressive—is less than the many millions of carbon-based compounds Often silicon is combined with oxygen in long chains that use the oxygen atoms as separators. Because oxygen has a valence of two, meaning that it can bond to two other atoms at a time, it bonds easily between two other silicon atoms. The silicon, meanwhile, has two other electrons to use in bonding, so it typically attaches to two more, non-bridging, oxygen atoms.

Compounds of this type are known as silicates, and most of the rocks and clay on Earth—with the exception of lime, which is calcium oxide—are silicates made up of combinations of silicon, oxygen, and various metals such as aluminum, iron, sodium, and potassium. Silicones are another variety of compound involving silicon atoms strung together by bridging oxygen atoms. Instead of attaching to two other, non-bridging oxygen atoms, as in a silicate, the silicon atoms in a silicone attach to organic groups—that is, molecules containing carbon. Because silicones often resemble organic compounds such as oils, greases, and rubber, silicone oils are frequently used in place of organic petroleum as a lubricant because they can withstand greater variations in temperature. Silicone rubbers are used in everything from bouncing balls to space vehicles. And because the body tolerates the introduction of silicone implants better than it does organic ones, silicones are used in surgical implants as well. The many other uses of silicon Silicones are also present in electrical insulators, rust preventives, fabric softeners, hair sprays, hand creams, furniture and automobile polishes, paints, adhesives (including bathtub sealers), and chewing gum.

Yet even this list does not exhaust the many applications of elemental silicon, as opposed to silicone. Due to its semi-metallic qualities, silicon is used as a semiconductor of electricity. Computer chips are tiny slices of ultra-pure silicon, etched with as many as half a million microscopic and intricately connected electronic circuits. These chips manipulate voltages using binary codes, for which 1 means “voltage on” and 0 means “voltage off.” By means of these pulses, silicon chips perform multitudes of calculations in seconds—calculations that would take humans hours or months or even years. A porous form of silica, known as silica gel, absorbs water vapor from the air, and is often packed alongside moisture-sensitive products such as electronics components, in order to keep them dry. Silicon carbine, an extremely hard crystalline material manufactured by fusing sand with coke (almost pure carbon) at high temperatures, has applications as an abrasive. Arsenic Silicon is unquestionably the “star” of the metalloids, but several other elements in this broad grouping have been known since ancient times. Among these is arsenic, well-known from many a detective novel.

Highly poisonous, it is often a fixture of such stories: in a typical plot, a greedy nephew drops some arsenic into the tea of an elderly aunt who has left money to him in her will, and it is up to the detective/hero/heroine to uncover the details behind this dastardly scheme. The use of arsenic as a prop in such tales had already become something of a cliche by 1941, when “Arsenic and Old Lace,” a play by Joseph Kesselring that satirized an old-fashioned “whodunit,” made its debut on Broadway. Known since ancient times, arsenic is named after the Greek word arsenikon, meaning “yellow orpiment.” (Orpiment is arsenic trisulfide, or As2S3.) But the Greeks were not the only peoples in antiquity who knew of arsenic and its toxic properties: the Egyptians and Chinese were likewise familiar with it.

Alchemists took an interest in arsenic, and one of them, Albertus Magnus (1193-1280)—a German physician who contributed significantly to the rebirth of interest in science during the late Middle Ages—probably isolated the element from arsenic trisulfide in about 1250. Arsenic is more than just a prop in a detective story. (And in fact it is not a very effective poison for a murderer who hopes to get away with his crime: traces of arsenic remain in the body of a murder victim—even in the person’s hair—for years after death.) Today, arsenic is used for purposes such as bronzing, and for hardening and improving the sphericity (roundness) of lead shot in shotgun shells. In solid-state devices such as transistors, arsenic or antimony is used for the purposes of “doping.” This may sound like another version of the whodunit-style poisoning described above, but actually doping involves the alteration of chemical properties by deliberately introducing impurities. Through the doping of silicon, its electrical conductivity is improved. Antimony In ancient times, antimony was known by the Latin name stibium; hence its chemical symbol of Sb.

The word, which can be deciphered as “a metal that does not occur by itself,” has roots much older than the Roman civilization, however. Many centuries before the rise of the Romans, the biblical prophet Jeremiah railed against women’s use of”stibic stone” to paint their faces. In fact, stibic stone is antimony (III) sulfide, or Sb2S3, a black mineral which has long been used as an eyeliner. During the Middle Ages, alchemists studied antimony and its compounds, but the first scientist to distinguish between the compounds and the element itself was French chemist Jean-Bap-tiste Buquet, in 1771. During the early modern era, antimony was used in making bells, tools, and type for printing presses, because its addition to an alloy strengthened the other metals. Today, antimony is added to lead in storage batteries to make the lead harder and stronger. It is still used in metal type, as well as bullets and cable sheathing. Antimony was a component in early varieties of matches, but by 1855, the less volatile phosphorus had replaced it. In altered form, however, antimony still appears in some matches.

Oxides and sulfides of antimony are also applied in paints, ceramics, fireworks, pharmaceuticals, and other products. These are also utilized for dyeing cloth and fireproofing materials. In addition, as noted above with regard to arsenic, antimony is applied for the doping of silicon and other materials in semiconductors, particularly those that use infrared detectors. Tellurium When Hungarian chemist Joseph Ramacsahazy first described tellurium in the mid-eighteenth century, he did so in alchemical terms, referring to it as “unripe gold.” This reflected the belief, still lingering from the Middle Ages, that metals “grow” to higher states. At least part of his confusion is understandable, since the element did appear in minerals that also contained gold. A few years later, Baron Franz Joseph Muller von Reichenstein, an Austrian mining inspector in Transylvania, analyzed the substance, which he concluded was bismuth sulfide. Later he changed his mind, then subjected the material to a series of tests over a period of many years, until finally he sent a sample to the distinguished German chemist, Martin Heinrich Klaproth (1743-1817).

Klaproth concluded that it was indeed a new element, and suggested the Latin word tellus, for “earth,” as a name. Grayish-white and lustrous, tellurium looks like a metal, but it is much more brittle than most metallic elements. Furthermore, it is a semiconductor, which further separates it from the typically conductive metals. Its semiconductive properties have led to applications in building electronic components. Added to copper and stainless steel, tellurium improves the machin-ability of those metals; in addition, tellurium compounds are used for the coloring of glass, porcelain, enamel, and ceramics. Germanium and Polonium Germanium. Both named after European countries, germanium and polonium were identified much later than the other metalloids.

In 1871, two years after he created his famous periodic table, Russian chemist Dmitri Ivanovitch Mendeleev (1834-1907) predicted the existence of an element he called “eka-silicon.” This turned out to be germanium, which sits directly beneath silicon on the periodic table, and which was discovered in 1886 by German chemist Clemens Alexander Winkler (1838-1904). Germanium is principally used as a doping agent in making transistor elements. It is also used as a phosphor in fluorescent lamps. In addition, germanium and germanium oxide, transparent to the infrared portion of the electromagnetic spectrum, are present in infrared spectroscopes and infrared detectors. Polonium While the applications of germanium are limited compared to those of, say, silicon, polonium is useful primarily as a source of neutrons in atomic laboratories—hardly something with which a person comes in contact during the course of an ordinary day.

Yet the isolation of polonium by Polish-French physicist and chemist Marie Curie (1867-1934), along with her husband Pierre (1859-1906), a French physicist, was a prelude to one of the greatest stories in the history of chemistry. Key Terms Ion: An atom or group of atoms that has lost or gained one or more electrons, and thus has a net electric charge. Isotopes: Atoms that have an equal number of protons, and hence are of the same element, but differ in their number of neutrons. This results in a difference of mass. Isotopes may be either stable or unstable. The latter type, known as radioisotopes, are radioactive. Metalloids: Elements which exhibit characteristics of both metals and non-metals. Metalloids are all solids, but are not lustrous or shiny, and they conduct heat and electricity moderately well. The six metalloids occupy a diagonal region between the metals and nonmetals on the right side of the periodic table.

Sometimes boron and astatine are included with the metalloids, but in this volume, they are treated as an “orphan” nonmetal and a halogen, respectively. Metals: Elements that are lustrous, or shiny in appearance, and malleable, meaning that they can be molded into different shapes without breaking. They are excellent conductors of heat and electricity,and tend to form positive ions by losing electrons. Nonmetals: Elements that have a dull appearance; are not malleable; are poor conductors of heat and electricity; and tend to gain electrons to form negative ions. They are thus the opposite of metals in most regards, as befits their name. North american system: A version of the periodic table of elements that only numbers groups of elements in which the number of valence electrons equals the group number—that is, the two “tall” columns to the left of the transition metals, as well as the six “tall” columns to the right. “orphan”: An element that does not belong to any clearly defined family of elements.

The metalloids are all “orphans.” Radioactivity: A term describing a phenomenon whereby certain isotopes known as radioisotopes are subject to a form of decay brought about by the emission of high-energy particles. “Decay” does not mean that the isotope “rots”; rather, it decays to form another isotope until eventually (though this may take a long time) it becomes stable. Setting out to find radioactive elements other than uranium, the Curies refined a large quantity of pitchblende, an ore commonly found in uranium mines. Within a year, they had discovered polonium, which Marie named after her homeland. Polonium is about 100 times as radioactive as uranium, but the Curies were certain that yet another element lay in the pitchblende, and they devoted the next four years to the exhausting process of isolating it. The story of radium, its isolation, and the great price Marie Curie paid for working with radioactive materials is discussed in the essay on Alkaline Earth Metals.

Question: Boron, silicon, germanium, arsenic, antimony and tellurium are commonly considered the six primary chemical element?
Answer: Metalloids