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English → English (gcide) Definition: chemical atomic weights Element \El"e*ment\, n. [F. ['e]l['e]ment, L. elementum.] 1. One of the simplest or essential parts or principles of which anything consists, or upon which the constitution or fundamental powers of anything are based. [1913 Webster] 2. One of the ultimate, undecomposable constituents of any kind of matter. Specifically: (Chem.) A substance which cannot be decomposed into different kinds of matter by any means at present employed; as, the elements of water are oxygen and hydrogen. [1913 Webster] Note: The elements are naturally classified in several families or groups, as the group of the alkaline elements, the halogen group, and the like. They are roughly divided into two great classes, the metals, as sodium, calcium, etc., which form basic compounds, and the nonmetals or metalloids, as oxygen, sulphur, chlorine, which form acid compounds; but the distinction is only relative, and some, as arsenic, tin, aluminium, etc., form both acid and basic compounds. The essential fact regarding every element is its relative atomic number, which is equal to the number of protons in the nucleus, and also equal to the number of electrons in orbitals around the nucleus when the atom is neutral. When the elements are tabulated in the order of their ascending atomic numbers, the arrangement constitutes the series of the Periodic law of Mendelejeff. See Periodic law, under Periodic. This Periodic law enables us to predict the qualities of unknown elements. The number of elements known in 1890 were about seventy-five, but at that time the gaps in the Periodic law indicated the possibility of many more. All of the elements up to atomic number 100 have now been observed though some are radioactive and very unstable, and in some cases cannot be accumulated in quantity sufficient to actually see by eye. The properties predicted by the periodic law wre close to the observed properties in many cases. Additional unstable elements of atomic number over 100 are observed from time to time, prepared in cyclotrons, particle acclerators, or nuclear reactors, and some of their properties are measurable by careful observation of microscopic quantities, as few as several atoms. For such unstable elements, the properties are now predicted primarily by calculations based on quantum mechanics. Such theories suggest that there may be an “island” of relative stability of elements of atomic number over 120, but this has yet to be confirmed by experiment. Many of the elements with which we are familiar, as hydrogen, carbon, iron, gold, etc., have been recognized, by means of spectrum analysis, in the sun and the fixed stars. The chemical elements are now known not be simple bodies, but only combinations of subatomic particles such as protons, neutrons, and electrons; ahd protons and neutrons are now believed to be themselves combinations of quarks, particles which are not observed singly, but only in combinations. In formulas, the elements are designated by abbreviations of their names in Latin or New Latin, given in the table below. The atomic weights given in the table below are the chemical atomic weights, in some cases being the weighted average of the atomic weights of individual isotopes, each having a different atomic weight. The atomic weight of the individual isotopes are called the physical atomic weights. In those few cases where there is only one stable isotope of an element, the chemical and physical atomic weights are the same. The mass-spectrometric atomic weights are those used for careful mass-spectrometric measurements. For more details about individual elements, see the element names in the vocabulary The Elements ---------------------------------------------------------- Name |Sym-| Atomic Weight | |bol | O=16 | H=1 | C=12.000 ---------------------------------------------------------- Aluminum | Al | 27.1 | 26.9 | Antimony (Stibium) | Sb | 120 | 119.1 | Argon | A | 39.9 | 39.6 | Arsenic | As | 75 | 74.4 | Astatine | At | Barium | Ba | 137.4 | 136.4 | Beryllium | Be | Bismuth | Bi | 208.5 | 206.9 | Boron | B | 11 | 10.9 | Bromine | Br | 79.96 | 79.36| Cadmium | Cd | 112.4 | 111.6 | Cesium (Caesium) | Cs | 133 | 132 | Calcium | Ca | 40 | 39.7 | Carbon | C | 12 | 11.91| 12.000 Cerium | Ce | 140 | 139 | Chlorine | Cl | 35.45 | 35.18| Chromium | Cr | 52.1 | 51.7 | Cobalt | Co | Columbium (see Beryllium) Copper | Cu | (Cuprum) Erbium | Er | Europium | Eu | Einsteinium | Es | Fermium | Fe | Fluorine | F | Gadolinium | Gd | Gallium | Ga | Germanium | Ge | Glucinum (now Beryllium) Gold (Aurum) | Au | Helium | He | Hydrogen | H | Indium | In | Iodine | I | Iridium | Ir | Iron | Fe | (Ferrum) Krypton | Kr | Lanthanum | La | Lead | Pb | (Plumbum) Lithium | Li | Magnesium | Mg | Manganese | Mn | Mercury | Hg | (Hydrargyrum) Molybdenum | Mo | Neodymium | Nd | Neon | Ne | Nickel | Ni | Niobium | Nb | (see Columbium) Nitrogen | N | Osmium | Os | Oxygen | O | Palladium | Pd | Phosphorus | P | Platinum | Pt | Potassium | K | (Kalium) Praseodymium | Pr | Rhodium | Rh | Rubidium | Rb | Ruthenium | Ru | Samarium | Sa | Scandium | Sc | Selenium | Se | Silicon | Si | Silver | Ag | (Argentum) Sodium | Na | (Natrium) Strontium | Sr | Sulphur | S | Tantalum | Ta | Tellurium | Te | Thallium | Tl | Thorium | Th | Thulium | Tu | Tin | Sn | (Stannum) Titanium | Ti | Tungsten | W | (Wolframium) Uranium | U | Vanadium | V | Wolfranium (see Tungsten) Xenon | X | Ytterbium | Yb | Yttrium | Y | Zinc | Zn | Zirconium | Zr | ---------------------------------------------------------- [1913 Webster] Note: Several other elements have been announced, as holmium, vesbium, austrium, etc., but their properties, and in some cases their existence, have not yet been definitely established. [1913 Webster] 3. One of the ultimate parts which are variously combined in anything; as, letters are the elements of written language; hence, also, a simple portion of that which is complex, as a shaft, lever, wheel, or any simple part in a machine; one of the essential ingredients of any mixture; a constituent part; as, quartz, feldspar, and mica are the elements of granite. [1913 Webster] The simplicity which is so large an element in a noble nature was laughed to scorn. --Jowett (Thucyd.). [1913 Webster] 4. (a) One out of several parts combined in a system of aggregation, when each is of the nature of the whole; as, a single cell is an element of the honeycomb. (b) (Anat.) One of the smallest natural divisions of the organism, as a blood corpuscle, a muscular fiber. [1913 Webster] 5. (Biol.) One of the simplest essential parts, more commonly called cells, of which animal and vegetable organisms, or their tissues and organs, are composed. [1913 Webster] 6. (Math.) (a) An infinitesimal part of anything of the same nature as the entire magnitude considered; as, in a solid an element may be the infinitesimal portion between any two planes that are separated an indefinitely small distance. In the calculus, element is sometimes used as synonymous with differential. (b) Sometimes a curve, or surface, or volume is considered as described by a moving point, or curve, or surface, the latter being at any instant called an element of the former. (c) One of the terms in an algebraic expression. [1913 Webster] 7. One of the necessary data or values upon which a system of calculations depends, or general conclusions are based; as, the elements of a planet's orbit. [1913 Webster] 8. pl. The simplest or fundamental principles of any system in philosophy, science, or art; rudiments; as, the elements of geometry, or of music. [1913 Webster] 9. pl. Any outline or sketch, regarded as containing the fundamental ideas or features of the thing in question; as, the elements of a plan. [1913 Webster] 10. One of the simple substances, as supposed by the ancient philosophers; one of the imaginary principles of matter. (a) The four elements were, air, earth, water, and fire; Note: whence it is said, water is the proper element of fishes; air is the element of birds. Hence, the state or sphere natural to anything or suited for its existence. [1913 Webster] Of elements The grosser feeds the purer: Earth the Sea; Earth and the Sea feed Air; the Air those Fires Ethereal. --Milton. [1913 Webster] Does not our life consist of the four elements? --Shak. [1913 Webster] And the complexion of the element [i. e.,the sky or air] In favor's like the work we have in hand, Most bloody, fiery, and most terrible. --Shak. [1913 Webster] About twelve ounces [of food], with mere element for drink. --Cheyne. [1913 Webster] They show that they are out of their element. --T. Baker. Esp., the conditions and movements of the air. “The elements be kind to thee.” (b) The elements of the alchemists were salt, sulphur, and mercury. --Brande & C. [1913 Webster] 11. pl. The whole material composing the world. [1913 Webster] The elements shall melt with fervent heat. --2 Peter iii. 10. [1913 Webster] 12. pl. (Eccl.) The bread and wine used in the eucharist or Lord's supper. [1913 Webster] Magnetic element, one of the hypothetical elementary portions of which a magnet is regarded as made up. [1913 Webster]