Chemical elements abundance

Occurrence in Nature. About 99.6% of the earth s mass results from 32 of the chemical elements. The remaining 0.4% is apportioned among 64 elements, all of which are present as traces. Iodine is one of these 64. Estimates about abundance of the constituent elements of the Hthosphere place iodine 46th on a restricted Hst of 59 elements (37 very rare elements are excluded) and 61st on a Hst in which 96 elements are included. Iodine is, indeed, one of the scarcest of the nonmetaUic elements in the total composition of the earth (3). 

Silicon, a low density chemical element having nonmetallic chaiacteristics, is the second, after oxygen (50.5%), most abundant element in the lithosphere. Silicon occurs naturally in the form of oxides and silicates and constitutes over 25% of the earth s cmst (see Silica). 

Titanium is the ninth most abundant element ia the earth s cmst, at approximately 0.62%, and the fourth most abundant stmctural element. Its elemental abundance is about five times less than iron and 100 times greater than copper, yet for stmctural appHcations titanium s aimual use is ca 200 times less than copper and 2000 times less than iron. Metal production began in 1948 its principal use was in military aircraft. Gradually the appHcations spread to commercial aircraft, the chemical industry, and, more recently, consumer goods. 

Most of the chemical elements consist of mixtures of isotopes. Oxygen, atomic number 8, has three stable isotopes. The kind having mass number 16 is most abundant. About 99.76% of the oxygen atoms consist of this isotope. Only 0.04%... 

Taylor, S. R. (1964). Abundance of chemical elements in the continental crust A new table. Geochim. Cosmochim. Acta 28,1273-1285. 

The elements are the simplest form of matter. An element contains only one type of atom and cannot be decomposed into other chemical components. Of the more than 100 known chemical elements, only a few are found in nature in their pure form. Figure J shows three of these Diamonds are pure carbon, nuggets of pure gold can be found by panning in the right stream bed, and sulfur is found in abundance in its elemental form. 

Silicon (Si) is a nonmetallic chemical element of the carbon family (Group rva of the periodic table) and makes up 27.7 percent of the Earth s crust. It is the second most abundant element in the crust, being surpassed only by oxygen. 

Over 98% of the soil is made up of only eight major chemical elements, listed in Table 51, in order of decreasing abundance. The 90-odd others make up the remaining 2% many occur in the soil as secondary or minor elements, while a large number of still others are present in only very low, often trace, concentrations. Thus all soils contain main, minor, and trace elements combined into chemical compounds and aggregated into complex particles of varying shape, size, and chemical composition (see Textbox 8). 

Abstract. In this contribution we present the results based on high-resolution spectra of 45 clump stars of the Galactic field. The main atmospheric parameters and abundances of 12C, 13C, N, O and other mixing sensitive chemical elements were investigated. Elemental ratios in the sample of field stars are compared to the results available for evolved stars in open clusters and to the theoretical prediction of extra mixing in stellar interiors. 

Abstract. We have investigated the abundance of several chemical elements in two large stellar samples kinematically representative of the thin and the thick disks of the Galaxy. Chemical, kinematical and age data have been collected from high quality sources in the literature. Velocities (U,V,W) have been computed and used to select stars with the highest probability to belong to the thin disk and the thick disk respectively. Our results show that the two disks are chemically well separated. Both exhibit a decline of [a/Fe] with increasing [Fe/H]. A transition between the thin/thick disks stars is observed at 10 Gyr... 

Abstract. In an effort to determine accurate stellar parameters and abundances for a large sample of nearby stars, we have performed the detailed analysis of 350 high-resolution spectra of FGK dwarfs and giants. This sample will be used to investigate behavior of chemical elements and kinematics in the thick and thin disks, in order to better constrain models of chemical and dynamical evolution of the Galaxy. 

Abstract. The most recently discovered Galactic component - thick disk - still needs high-resolution spectral investigations since its origin and evolution is not understood enough. Elemental abundance ratios in the metallicity range —0.68 < [Fe/H] < —0.10 were determined in a sample of 10 thick-disk dwarfs and compared with results of other stars investigated as well as with models of thin disk chemical evolution. 

The existence and distribution of the chemical elements and their isotopes is a consequence of nuclear processes that have taken place in the past in the Big Bang and subsequently in stars and in the interstellar medium (ISM) where they are still ongoing. These processes are studied theoretically, experimentally and obser-vationally. Theories of cosmology, stellar evolution and interstellar processes are involved, as are laboratory investigations of nuclear and particle physics, cosmo-chemical studies of elemental and isotopic abundances in the Earth and meteorites and astronomical observations of the physical nature and chemical composition of stars, galaxies and the interstellar medium. 

Galactic chemical evolution of light elements Table 9.2. Results of simple calculations of light element abundances... 

Bernard Ephraim Julius Pagel was bom in Berlin on 4 January 1930, but when his father was dismissed from his post as Jewish persecution increased, the family moved to Britain in 1933. From Merchant Taylors School he won an open scholarship in Natural Sciences at Sidney Sussex College, Cambridge, graduating with First-class honours in Physics in 1950. His early research at Cambridge (Ph.D. 1955) centred on the solar atmosphere. Inspired by Willy Fowler, a future Nobel Prize winner who was visiting from California, he started a life-long interest in the abundances of the chemical elements. 

Abundances of chemical elements in rocks, sediments, and the continental crust of China... 

The data listed in Table 1 factually reflect abundances of chemical elements in various kinds of geological media of rocks, soils, sediments and in the continental crust of China, because the samples have a good representativity for various media and elements analyzed by high-quality analytical methods under strict quality... 

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