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Metals and Alloys

In this chapter you will learn:

  1. Properties of Metals

  2. Properties of Alloys

Properties of Metals

  • Metals are good conductors of thermal energy because energy is transferred through the delocalised electrons.

  • Metals have high density and very high melting and boiling points.

  • Metals are also malleable.

  • Metals are good conductor of heat due to the delocalised electrons..

  • Metallic bonds are very strong and a result of the attraction between the positive metal ions and the negative delocalised electrons.

  • In pure metals, atoms are arranged in layers, which allows metals to be bent and shaped without breaking the bonds. When a force is applied, the layers may slide over each other.

  • Pure metals are too soft for many uses and so are mixed with other metals to make alloys which are harder.

  • The layers of atoms in pure metals can slide over each other.

  • Properties of Alloys

  • Alloys are mixtures of metals.

  • Bronze is an alloy of copper and tin.

  • Brass is an alloy of copper and zinc.

  • Gold is an alloy with silver, copper and zinc.

  • Steels are alloys of iron that contain specific amounts of carbon and other metals.

  • Alloys can be made from metals mixed with nonmetals such as carbon.

  • Alloys are usually much harder than the pure metal.

  • Alloys contain atoms of different sizes. This makes difficult for the layers to slide over each other.

  • Alloys are used to make dental braces and coins. Nitinol is an alloy used in dental braces because the alloy is able to return its original shape.