Malleability of metals

The differing malleabilities of metals can be traced to their crystal structures. The crystal structure of a metal typically has slip planes, which are planes of atoms that under stress may slip or slide relative to one another. The slip planes of a ccp structure are the close-packed planes, and careful inspection of a unit cell shows that there are eight sets of slip planes in different directions. As a result, metals with cubic close-packed structures, such as copper, are malleable they can be easily bent, flattened, or pounded into shape. In contrast, a hexagonal close-packed structure has only one set of slip planes, and metals with hexagonal close packing, such as zinc or cadmium, tend to be relatively brittle. 

Malleability and Ductility The malleability of metals can be explained by viewing metallic bonds as being non-directional. The positive ions are often layered as fixed arrays (like soldiers lined up for inspection). When stress is applied to a metal, one layer of positive ions can slide over another layer. The layers move without breaking the array, which is the reason why metals do not shatter immediately along a clearly... 

For Stahl, as for Becher, water and earth were the key principles of chemical substances. Like Becher, Stahl said that there were three different kinds of earth, but he described these somewhat differendy from his mentor. There was metallic or mercurial earth, which accounted for the brightness and malleability of metals, their ability to be molded and worked by a goldsmith or blacksmith. Then came vitrffiable earth (earth that can be turned into a glassy substance), and this was what made substances able to melt. It was associated with the heavy, lumpish nature of minerals. Finally, there was sulfurous earth, also known as phlogistic earth or phlogiston, and this enabled bodies to burn and flame. These three earths were chemical principles. 

The defects we have discussed in this chapter are largely microscopic and cannot be observed from the macroscopic structure of the materials. However, there are various sorts of macroscopic defect which can be examined using electron microscopy, and which explain certain physical characteristics. For example, metals are generally malleable and ductile but their ordered solid state structure implies that they should be rigid. Sometimes heating metals makes them more brittle in a process known as work hardening . These characteristics indicate that the structures of the metals are not perfect. The malleability of metals is an indication that the structure contains defects which occur in lines and planes, allowing the atoms to slip over each other. As the temperature rises or the metal is worked (as by a blacksmith), the metal becomes harder as the defects are removed. 

A FIGURE 12.10 Malleabilty and ductility. Gold leaf demonstrates the charactetistic malleability of metals, and copper wire demonstrates their ductility. 

Physical properties of matter are those that can be measured without altering the chemical composition of the matter. A typical physical property is color, which can be observed without changing matter at aU. Malleability of metals, the degree to... 

The electron sea model also accounts for the malleability of metals (their capacity to be pounded into sheets) and the ductility of metals (their capacity to be drawn into wires). Since there are no localized or specific bonds in a metal, we can deform it relatively easily by forcing the metal ions to slide past one another. The electron sea easUy accommodates deformations by flowing into the new shape. 

Physical properties of matter are those that ean be measured without altering the ehemieal eomposition of the matter. A typieal physical property is eolor, which can be observed without changing matter at all. Malleability of metals, the degree to whieh they ean be pounded into thin sheets, eertainly alters the shape of an object but does not ehange it chemically. On the other hand, observation of a chemical property, sueh as whether sugar bums when ignited in air, potentially involves a eomplete ehange in the chemical composition of the substance tested. 

Nickel is silvery white and takes on a high polish. It is hard, malleable, ductile, somewhat ferromagnetic, and a fair conductor of heat and electricity. It belongs to the iron-cobalt group of metals and is chiefly valuable for the alloys it forms. 

Ductility and malleability. Most metals are ductile (capable of being drawn out into a wire) and malleable (capable of being hammered into thin sheets). In a metal, the electrons act like a flexible glue holding the atomic nuclei together. As a result, metal crystals can be deformed without shattering. 

Main-group elements, 153t Malleability The ability to be shaped, as by pounding with a hammer characteristic of metals, 244 Maltose, 618-619 Manometer, 104 Maple syrup, 277-278 Mass An extensive property reflecting the amount of matter in a sample, 7. See also Amount, critical, 525... 

Though the mechanical properties of the various metals differ, all metals can be drawn into wires and hammered into sheets without shattering. Here we find a fourth characteristic property of metals they are malleable or workable. 

Nickel. Ni, at wt 58.71, at no 28, valences +2 +3, five stable isotopes, 7 radioactive isotopes. Malleable, silvery metal readily fabricated by hot and cold working takes high polish excellent resistance to corrosion. Mp 1455° bp 2900° d 8.9Q8g/cc electrical resistivity (20°) 6.844 microhm-cm Moh s hardness 3.8 spec heat (100°) 0.1123 latent heat of fusion 73cal/g. 

They are malleable, that is, they can be shaped by applying an external pressure, as when hammering a lump of metal or alloy into different shapes or into thin sheets they are also ductile (can be drawn into wire), although cast iron is brittle. 

C). However, the characteristics of metals that physically distinguish them are their metallic luster, electrical conductivity, malleability, and ductility. Elements generally classified as metals exhibit wide variation in these properties. Chemically, metals are also reducing agents as a result of their having comparatively low ionization potentials. Another characteristic that differs enormously is their cost. Some of the base metals sell for a few cents per pound, whereas some of the exotic metals sell for a few thousand dollars per gram. 

The physical characteristics of metals that permit them to function as versatile materials for fabricating many items are their ductility, malleability, and strength. Although strength probably needs no explanation, the first two of these characteristics are related to the ability of the metal to be fabricated into a desired shape. Metals vary widely in these characteristics, and a metal or alloy that is well suited to one use may be entirely unsatisfactory for another. Addressing this branch of applied science is beyond the scope of this book, but a book on materials science provides a great deal of information that is relevant for students in inorganic chemistry. 

The rest of the elements, to the right of the metalloids, are called nonmetals. Nonmetals have properties that are often the opposite of metals. Some are gases, are poor conductors of heat and electricity, are neither malleable nor ductile, and tend to gain electrons in their chemical reactions to form anions. 

Interpreting Data Metals are usually malleable and good conductors of electricity. They are generally lustrous and silver or white in color. Many react with acids. Write the word metal beneath the Classification heading in the data table for those element samples that display the general characteristics of metals. 

The best choice of metal for making a minigrid is gold, because it is so malleable. 

Thorium is a radioactive, silvery-white metal when freshly cut. It takes a month or more for it to tarnish in air, at which point it forms a coating of black oxide. Although it is heavy, it is also a soft and malleable actinide metal. The metal has a rather low melting point, but its oxide has a very high melting point of about 3,300°C. Thorium reacts slowly with water but reacts more vigorously with hydrochloric acid (HCl). 

AH the isotopes of americium belonging to the transuranic subseries of the actinide series are radioactive and are artificially produced. Americium has similar chemical and physical characteristics and is hofflologous to europium, located just above it in the rare-earth (lanthanide) series on the periodic table. It is a bright-white malleable heavy metal that is somewhat similar to lead. Americiums melting point is 1,176°C, its boiling point is 2,607°C, and its density is 13.68g/cm. ... 

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