The solid material which is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity (e.g. iron, gold, silver, and aluminium, and alloys such as steel).
Physical properties of metals
- All metals except mercury exist as solids at room temperature. Metals have high melting points but gallium and caesium have very low melting points. These two metals will melt if you keep them on your palm.
- Metals, in their pure state, have a shining surface. This property is called metallic lustre.
- Metals can be beaten into thin sheets. This property is called malleability. Gold and silver are the most malleable metals.
- The ability of metals to be drawn into thin wires is called ductility. Gold is the most ductile metal.
- Metals are good conductors of heat and have high melting points. The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat.
- Metals, in general, have high densities.
Occurrence of Metals
The earth’s crust is the major source of metals. Seawater also contains some soluble salts such as sodium chloride, magnesium chloride, etc.
The elements or compounds, which occur naturally in the earth’s crust, are known as minerals.
At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.
|1||Aluminum (Al)||Bauxite (Al2O3.2H2O), Corundum (Al2O3), Cryolite (Na3AlF6)|
|2||Calcium (Ca)||Dolomite (CaMg(CO3)2), Limestone (CaCO3)|
|3||Copper (Cu)||Chalcocite (Cu2S), Chalcopyrite (CuFeS2), Malachite (Cu2CO3(OH)2)|
|4||Gold (Au)||Calaverite (AuTe2), Sylvanite ((Ag,Au)Te2)|
|5||Iron (Fe)||Hematite (Fe2O3), IronPyrite (FeS2), Magnetite (Fe3O4), Siderite (FeCO3)|
|6||Lead (Pb)||Anglesite (PbSO4), Galena (PbS)|
|7||Phosphorous (P)||Floreopetite (3Ca3(PO4)CaFe2), Phosphorite (Ca3(PO4)CaFe2)|
|8||Potassium (K)||Carnallite (KCl.MgCl2·6(H2O)), Saltpeter (KNO3)|
|9||Magnesium (Mg)||Magnesite (MgCO3), Dolomite (CaMg(CO3)2), Brucite (Mg(OH)2)|
|10||Mercury (Hg)||Calomel (Hg2Cl2), Cinnabar (HgS)|
|11||Silver (Ag)||Argentite/Acanthite (Ag2S)|
|12||Sodium (Na)||Rock Salt (NaCl), Washing Soda (Na2CO3)|
|13||Tin (Sn)||Cassiterite (SnO2), Tin Pyrites (Cu2FeSnS4)|
|14||Zinc (Zn)||Calamine (ZnCO3), Zinc Blende (ZnS)|
Some important facts about Metals and Their Ores
- Aluminium is the most abundant metal and third most abundant element in the Earth’s crust. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals.
- The most common metal ores are oxides and sulphides.
- Metal ores are generally oxides, sulfides, silicates, or native metals (such as native copper) that are not commonly concentrated in the Earth’s crust or noble metals (not usually forming compounds) such as gold.
- Rhodium is an extremely rare, valuable and silvery-coloured metal that is commonly used for its reflective properties.
- Platinum is the second-most valuable metal ore and is found in thin layers of sulfides.
- Though gold is often associated with wealth it is actually only the third-most valuable metal and is often found in small amounts in iron ores such as magnetite.
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