Chemical elements nonmetals

Krebs, Robert E. The history and use of our earth s chemical elements a reference guide. Westport (CT) Greenwood P, 1998. ix, 346p. ISBN 0-313-30123-9 A short history of chemistry — Atomic structure The periodic table of the chemical elements — Alkali metals and alkali earth metals - Transition elements metals to nonmetals — Metallics and metalloids - Metalloids and nonmetals — Halogens and noble gases - Lanthanide series (rare-earth elements) — Actinide, transuranic, and transactinide series... 

The 92 chemical elements that occur naturally in the earth can be divided into two main groups metals and nonmetals. Although the distinction between the two is not always sharp and clear, it can be said that over 70 of the 92 elements are metals among the fewer than 22 remaining non-metals, six are known as metalloids, which have properties that fall between those of metals and nonmetals (see Appendix I). 

In common parlance, the term metal is used to refer to two different types of metallic materials metals and alloys. The metals are chemical elements each metal (e.g., copper, iron, and gold) is composed of only one type of atom. The alloys are mixtures that have metallic properties. All alloys include two or more elements in their composition some are made up of two or more metals, others of one or more metals mixed with one or more nonmetals. Bronze, for example, is made up of two metals copper (60-85%) and tin (40-15%) steel includes iron, a metal (98-99.97%) and carbon, a nonmetal (2-0.03%). Metals and alloys share many common properties ... 

Chemical elements essential to life forms can be broken down into four major categories (1) bulk elements (H, C, N, O, P, S) (2) macrominerals and ions (Na, K, Mg, Ca, Cl, PO4A SC>4 ) (3) trace elements (Fe, Zn, Cu) and (4) ultratrace elements, comprised of nonmetals (F, I, Se, Si, As, B) and metals (Mn, Mo, Co, Cr, V, Ni, Cd, Sn, Pb, Li). The identities of essential elements are based on historical work and that done by Klaus Schwarz in the 1970s.1 Other essential elements may be present in various biological species. Essentiality has been defined by certain... 

Period 5 (group 3 [IIIB] to group 12 [IIB]) is located in the second row of the transition elements and represents 10 of the transition metals to nonmetals found in the periodical table of chemical elements. This period is also known to include some of the so-called rare-earth elements. Most of the rare-earths are found in the lanthanide series, which follows barium (period 6, group 3). (Check the periodic table to locate the major rare-earth elements in the lanthanide series. These are addressed in a later section of the book.)... 

The halogens are the family of nonmetal elements in group 17 (VIIA) that are located just to the right of the oxygen group 16 on the periodic table of chemical elements. They are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). 

A nonmetal is a chemical element that generally does not conduct heat or electricity very well, is usually... 

Semi-metals or metalloids are a very small group of elements found in the periodic table of elements along the zig-zag line that distinguishes metals from non-metals and is drawn from between boron and aluminum to the border between polonium and astatine. Elements to the upper right of this line are nonmetals while metals are to the lower left. Together with metals and nonmetals, metalloids form one of the three categories of chemical elements as classified by ionization and bonding properties [1, 2]. 

The names of a few chemical elements are very similar to the names of planets in the solar system. List these elements, along with their chemical symbols and atomic numbers. Tell whether each element is a metal, nonmetal, or metalloid. 

The most fundamental classification of the chemical elements is into metals and nonmetals. Metals typically have the following physical proper-fies a lustrous appearance, the ability to change shape without breaking (they can be pulled into a wire or pounded into a thin sheet), and excellent conductivity of heaf and elecfricity. Nonmetals fypically do nof have these physical properties, although there are some exceptions. (For example, solid iodine is lustrous the graphite form of carbon is an excellent conductor of elecfricity and the diamond form of carbon is an excellent conductor of heaf.) However, it is the chemical differences between metals and nonmetals that interest us the most ... 

The 17 elements to the right and above the line are nonmetals. Nonmetals have a strong tendency to gain electrons when forming a chemical bond. Nonmetals may be solids, liquids, or gases all are poor conductors of heat and electricity. Solid nonmetals are either hard and brittle or soft and crumbly. 

In general, the elements that appear in the lower-left region of the periodic table have the lowest ionization energies (and are therefore the most chemically active metals). On the other hand, the elements with the highest ionization energies (the most chemically active nonmetals) occur in the upper-right region of the periodic table. 

With an electronegativity only slightly above the median value of all the chemical elements, hydrogen behaves like a weakly electronegative non-metal. It forms ionic compounds with very electropositive metals and covalent compounds with nonmetals. It also forms metal hydrides with some of the transition metals. The three major hydrides it forms and with which elements are shown in Figure 10-2. 

FIGURE 3-17 The elements can be broadly divided Into metals, which primarily lose electrons In chemical reactions nonmetals, which primarily gain electrons In chemical reactions and metalloids, which can do either. 

Interstitial Compounds. Tungsten forms hard, refractory, and chemically stable interstitial compounds with nonmetals, particularly C, N, B, and Si. These compounds are used in cutting tools, stmctural elements of kilns, gas turbines, jet engines, sandblast nozzles, protective coatings, etc (see also Refractories Refractory coatings). 

FIGURE B.12 The location ot the seven elements commonly regarded as metalloids these elements have characteristics of both metals and nonmetals. Other elements, notably beryllium and bismuth, are sometimes included in the classification. Boron (B), although not resembling a metal in appearance, is included because it resembles silicon (Si) chemically. 

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