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Types of Metals Help (page 2)

By — McGraw-Hill Professional
Updated on Aug 28, 2011

Alkaline Earth Metals

The Periodic Table is great for placing elements according to their characteristics. An element’s location provides information about its “personality” and uses.

Barium’s location in group IIA shows that it is an alkaline earth metal. Like calcium and magnesium, barium has applications in medicine as barium sulfate (opaque to X-rays and used to check out the digestive tract) and photography (a whitener in photographic papers). Barium helps doctors to differentiate between physiological structures.

Iron

Next in the list of commonly known metals, after gold, silver, and copper, is iron. Iron was discovered thousands of years ago and frequently used as a marker for the progress of human civilizations. This time of early discovery from pre-history until about 1100 became known as the Iron Age.

Iron, a reddish brown metal, is the “friendliest” of the metals. It readily combines with many other elements to form a huge variety of products known for their strength, since primitive times, like hand tools, cups, and plows to name just a few. Iron is the fourth most plentiful element in the Earth’s crust making up about 5% of the elements present. Currently, more than 90% of all metal refined in the world is iron.

Iron is found in several ores, the main one being hematite (Fe 2 O 3 ). Hematite has different colors and forms. The silvery black ore is used for jewelry and sometimes thought of as heavy, black “pearls.” The red form of hematite is used in paint pigments and is known as the color, red ocher.

Alloys

Other metals, such as chromium, manganese, nickel, tungsten, cobalt, and chromium, combine with iron to make steel, an alloy of superior strength, hardness, and durability. About 99% of all iron mined in the world today goes into the manufacture of steel.

Alloys are formed by the combination of two or more metals or a metal and non-metal.

When iron is coated with zinc, it is resistant to the rusting effects of oxygen and is said to be galvanized . Nails, wire, and large sheets of metal are treated this way to increase the life and use of such metals.

By mixing metals of different characteristics, in different proportions, a new metal or metal alloy can be created. The metals are melted together into a molten solution, cooled, and allowed to become solid again. The newly formed solid has the characteristics of its parent metals along with new properties, such as greater strength than either of its parents. (Example: steel = 80% iron, 12% chromium, 8% nickel; alloy manganese steel = 87% iron, 12% manganese, 1% carbon (railroad rails). Iron alloys are made by mixing together two or more molten metals and a non-metal. When producing 10-carat, 14-carat, and 18-carat gold, various percentages of gold, copper, and silver are used. Table 12.2 gives examples of commonly used alloys and their composition.

Table 12.2 When metals are mixed in set quantities, alloys of specific properties are made.

Metals Alloys

Mercury is prized by scientists for its ability to dissolve other metals and form alloys. When combined with silver, dentists make a silver-mercury amalgam (alloy) to fill cavities in teeth. Mercury also dissolves gold and is used in the collection of gold from other ores.

Practice problems for these concepts can be found at – Chemistry and Metals Practice Test

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