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Metals & Non-metals

Metals & Non-metals. What is a metal?. What is a non-metal?. Commonly available metal forms.

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Metals & Non-metals

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  1. Metals & Non-metals

  2. What is a metal? What is a non-metal?

  3. Commonly available metal forms • The basic elements of all metals are found naturally occurring within the earth. After they are extracted in the from of ore they are refined and processed in a variety of ways to produce usable materials. Metals are commonly available for manufacturing use in a wide range of forms and sizes. www.afcd.gov.hk/.../cou_vis_cou_mos.html Mining for Iron Ore in Ma On Shan until 1981 http://thomonthenet.com/ContemporaryGlass/JoshSimpson_Megaworld13_large.jpg www.ferretrollforming.com/aboutus.htm

  4. What is A Metal? • A metal may be defined as an element that can ionize by losing electrons. • A metal is located on the left hand side of the periodic table. • Most metals can be found from natural sources in the earth’s crust.

  5. What Is A Non-metal? • A non-metal may be defined as an element that can ionize by gaining electrons. • Non-metals are located on the right hand side of the periodic table and are found in the earths atmosphere and in compounds in the earths crust.

  6. Properties of a metal Metals have a shiny or metallic luster Metals are a good conductors of heat and electricity. At room temperature most metals are a solid Metals are malleable and tend to be ductile because of their high tensile strength Most metals tend to lose electrons

  7. Properties of Non-metals Most Non-metals are dull Non-metals are poor conductors of heat and electricity At room temperatures most non-metals are gases Solid non-metals tend to be brittle rather than malleable or ductile. Non-metals tend to gain electrons

  8. What is an alloy? • An alloy is a mixture of two or more metals • e.g. brass = copper + zinc • or a mixture of a metal with small amounts of non-metals • e.g. steel = iron + carbon

  9. Why are metals often used in the forms of alloys? • Pure metals - soft and malleable • Alloy - the size of the atoms of the added element is different from that of the main metal. This breaks up the regular packing of metal atoms and prevents the slip because the atoms of different sizes cannot slide over each other. • If slip cannot occur, then the alloy is harder and less malleable.

  10. What are the main reasons for making alloys? • to improve the strength and hardness of metals, • to improve the resistance of metals against corrosion, • to improve the appearance of the metal • to lower the melting point of the metal.

  11. What is a displacement reaction? • A displacement reaction is a process m which a metal dissolves in the solution and becomes an ion while the metal which is in the ionic form in the solution becomes a metal. • A metal higher in the reactivity series will displace any metal that is lower in the series from its solution. This is called a displacement reaction.

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