Natural Sources of the Metallic Elements

Left Power transmission lines the wires are aluminum.R/ghf Aluminum and copper wire. 

A metal need not be a pure element it can be a compound or mixture. An alloy is a material with metallic properties that is either a compound or a mixture. If the alloy is a mixture, it may be homogeneous (a solution) or heterogeneous. Most commercial metals are alloys consisting usually of one metal with small quantities of some other metals. Gold jewelry, for example, is made from an alloy that is a solid solution of gold containing some silver. Pure gold is too soft for jewelry the alloy is much harder. 

In the first part of this chapter, we will look at the different sources of the metallic elements and see how we obtain the free metals from their ores. We will also look at the bonding in metals, which can explain some of their properties. 

The Pictured Rocks along the shore of Lake Superior in Michigan are sandstone cliffs composed principally of silicon and oxygen.The beautiful colors of the cliffs are due to streaks of hematite, or iron(lll) oxide. 

A major source of metals and their compounds is the earth s crust, the outer solid portion of the planet. Mine shafts go to depths of less than about 4 km (compared with the earth s radius of 6371 km) therefore, we access only the thinnest outer layer of the earth. Table 13.1 lists the ten most abundant elements in the earth s crust and the mass percentage of each element in this part of the earth. 

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In this chapter, we ll look at both metals and solid-state materials. We ll examine the natural sources of the metallic elements, the methods used to obtain metals from their ores, and the models used to describe the bonding in metals. We ll also look at the structure, bonding, properties, and applications of semiconductors, superconductors, ceramics, and composites. 

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