The chemical elements

The above is the modern recommended form of the table using 18 groups. Older group designations are shown below. 

There are two basic types of elements metals and nonmetals. The metals, such as copper, gold, and iron (see Chapter 5), make up more than three-quarters of the total number of elements nonmetals, such as, for example, chlorine, sulfur and carbon, make up much of the rest. Other elements, however, known as the metalloids or semimetals, have properties intermediary between the metals and the nonmetals (see Appendix I). Only a few elements, such as the metals gold and copper and the nonmetal sulfur, which are known as the native elements, occur in nature uncombined. Most elements occur naturally combined with others, forming compounds. It is from these compounds, which occur in the crust of the earth as minerals, rocks, or sediments, that humans extract most of the elements that they require (Klein 2000). 

Archaeological Chemistry, Second Edition By Zvi Goffer Copyright 2007 John Whey Sons, Inc. 

84 others including, in descending order of abundance, titanium, hydrogen, phosphorus, barium, and strontium. 1.5 

Elements The chemical elements, or simply elements, such as gold, oxygen, and the 110 others listed in Appendix I, cannot be separated into other, simpler substances by any means. There are 112 known chemical elements 

Solutions Solutions are homogeneous forms of matter that may be composed of a solid dissolved in a liquid - such as common salt dissolved in water a gas dissolved in a liquid - for example, oxygen dissolved in water or a solid dissolved in another - for example, carbon dissolved in iron in some alloys of this metal. The composition and properties of each solution are determined by the nature of the components and the relative amount of each component in the solution (see Table 2). 

Because particles are so far apart, there is usually no significant attraction between them. 

Particles move in straight paths, changing direction and speed when they collide. 

Objective 10 Unlike the liquid, which has a constant volume, the rapid, ever-changing, and 

You can review the information in this section and see particles of solids, liquids, and gases in motion at the textbook s Web site. 

the water can be broken down into two even simpler substances-hydrogen gas and oxygen gas-by running an electric current through it. Also, we can melt the dry salt and then run an electric current through it, which causes it to break down into sodium metal and chlorine gas. 

A kind of matter consisting of atoms that all have nuclei with the same electric charge is called an element. 

For example, all of the atoms that contain nuclei with the charge -t-e. 

An elementaiy substance is a substance that is composed of atoms of one element only. An elementary substance is commonly called an element. 

Diagram showing the regular change of wavelength of x-ray emission lines for a series of elements. 

sulfur, tin, and a few other substances that occur in Earth s crust were recognized as elements long before the modem meaning of the term developed. Other naturally occurring elements were identified only after long and laborious efforts to separate them from the compounds in which they are found. Although it isn t always easy, chemists can now separate and identify the elements present in the most complex mixtures and compounds. 

The names of the elements are listed inside the front cover of this book. About 18 of these elements are not found anywhere in nature, but have only been produced artificially in laboratories, usually in extremely small quantities. 

The elements range widely in their properties. As is discussed in Chapter 3 and represented by the arrangement of the elements in the periodic table (inside the front cover of this book), the properties of the elements are largely determined by the composition of their atoms. 

Under everyday conditions some elements, including helium, hydrogen, nitrogen, oxygen, and chlorine, are gases. Only two elements—mercury and bromine—are ordinarily liquids. Most of the elements are solids, and of these most are silvery metals. Two distinguishing properties of metals are that they conduct electric current and have a shiny appearance. A second major class of elements, the nonmetals, do not conduct electricity and are not lustrous. The familiar nonmetals include all the elemental gases, and carbon, sulfur, phosphorus, and iodine, which are solids. 

Since elements are the building blocks of all matter, symbols for the elements are fundamental to communicating about chemistry. The symbols for the elements are listed next to their names inside the front cover of this 

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Nesmeyanov, A. N. "Vapor Pressure of the Chemical Elements," Elsevier, New York, 1963. 

The Wiswesser Line Notation (WLN) was introduced in 1946, in order to organize and to systematically describe the cornucopia of compounds in a more concise manner. A line notation represents a chemical structure by an alphanumeric sequence, which significantly simplifies the processing by the computer [9-11], (n many cases the WLN uses the standard symbols for the chemical elements. Additionally, functional groups, ring systems, positions of ring substituents, and posi-... 

For nearly half a century, Mendeleev s periodic table remained an empirical compilation of the relationship of the elements. Only after the first atomic model was developed by the physicists of the early twentieth century, which took form in Bohr s model, was it possible to reconcile the involved general concepts with the specificity of the chemical elements. Bohr indeed expanded Rutherford s model of the atom, which tried to connect the chemical specificity of the elements grouped in Mendeleev s table with the behavior of electrons spinning around the nucleus. Bohr hit upon the idea that Mendeleev s periodicity could... 

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). 

N. V. Sidgwick, The Chemical Elements and Their Compounds, Oxford University Press, London, 1950, pp. 948—994. 

Analytical x-ray instruments ate used to characterize materials in several different ways. As with medical x-ray instmments there are analytical instmments that can produce images of internal stmctures of objects that are opaque to visible light. There are instmments that can determine the chemical elemental composition of an object, that can identify the crystalline phases of a mixture of soHds, and others that determine the complete atomic and molecular stmcture of a single crystal. These ate the most common appHcations for x-ray iastmments. 

EXAMINATION OF THE CHEMICAL ELEMENTS RATIOS IN HUMAN NAILS (SRXRF)... 

DEF. The components are the chemical elements which make up the alloy. 

W- A, Fowler (Cahfomia Institute of Technology, Pasadena) theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe. 

We have been much encouraged by the careful assessment and comments on individual chapters by numerous colleagues not only throughout the U.K. but also in Australia, Canada, Denmark, the Federal Republic of Germany, Japan, the U.S.A and several other countries. We believe that this new approach will be widely welcomed as a basis for discussing the very diverse behaviour of the chemical elements and their compounds. 

Thus, each of the chemical elements consists of atoms whose nuclei contain a particular number of protons, hence a particular nuclear charge. The number of protons in the nucleus is called the... 

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%... 

Knight, D. M. (ed.) (1970) Papers on the Nature and Arrangement of the Chemical Elements, Classic Scientific Papers, 2nd series (New York Elsevier). 

Mendeleev, D, I. (1879a) The Periodic Law of the Chemical Elements , The Chemical News and Journal of Physical Science 40, 78-79. 

Arguably, however, Mendeleev s greatest achievement was not the periodic table so much as the recognition of the periodic system on which it was based. Of the nearly 1,000 variations that have been published since, all are attempts to represent the fundamental rule that after certain but varying intervals, the chemical elements show an approximate repetition in their properties. 

The formation of the combination of defects may be described as a chemical reaction and thermodynamic equilibrium conditions may be applied. The chemical notations of Kroger-Vink, Schottky, and defect structure elements (DSEs) are used [3, 11]. The chemical reactions have to balance the chemical species, lattice sites, and charges. An unoccupied lattice site is considered to be a chemical species (V) it is quite common that specific crystal structures are only found in the presence of a certain number of vacancies [12]. The Kroger-Vink notation makes use of the chemical element followed by the lattice site of this element as subscript and the charge relative to the ideal undisturbed lattice as superscript. An example is the formation of interstitial metal M ions and metal M ion vacancies, e.g., in silver halides ... 

The expressions in parentheses may be varied independently. These correspond to the Schottky building units. In the latest notation, interstitials are indicated by the chemical elements without any subscript, and vacancies are indicated by the missing chemical element between two vertical lines. Equations (5) or (6) then read ... 

All matter is made up of various combinations of the simple forms of matter called the chemical elements. An element is a substance that consists of only one kind of atom. 

Not surprisingly, only about 20 of the chemical elements found on Earth are used by living organisms (Chapters 3 and 8). Most of them are common elements. Rare elements are used, if at all, only at extremely low concentrations for specialized functions. An example of the latter is the use of molybdenum as an essential component of nitrogenase, the enzyme that catalyzes the fixation of elemental dinitrogen. Because they are composed of common elements, living organisms exert their most profound effects on the cycles of those elements. 

Goldschmidt VM (1929) The Distribution of the Chemical Elements. Proceedings of the Royal Institution of Great Britain 26 73-86, as quoted in Mason B, Victor Moritz Goldschmidt Father of Modern Geochemistry, The Geochemical Society San Antonio TX184 pp. 

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