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Silver
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Symbol
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Ag
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Atomic weight
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107.868
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Atomic number
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47
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discovery
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Known since prehistoric time. Man learned to separate silver from lead early as 3000B.C.
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Word origin
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Anglo-Saxon seolfor or siolfur, meaning 'silver' and Latin argentums.
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Melting point
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961 degree centigrade
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Boiling point
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2212 degree centigrade
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Specific gravity
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10.50 (200C)
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Electrical resistivity
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1.5*10-8 ohm-m
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Properties:
1. Pure silver has a brilliant white luster.
2. It is very ductile and malleable, exceeded in these properties by gold and palladium.
3. It has the highest electrical and thermal conductivity of all metals.
4. It has a low surface contact resistance.
5. In order to make it harder 15% of copper is added into it. To make it more hard for use in commutate segment of small dc. Motors as alloy of silver-copper containing 40% of copper is used.
6. It is superior to copper in its resistance to oxidation.
Uses:
1. The alloys of silver have many commercial uses. Sterling silver (92.5% silver, with copper or other metals) is used for silver ware and jewellery.
2. Silver is used in photography, dental compounds, solder, brazing, electrical contacts, batteries, mirrors and printed circuits.
3. Silver chloride can be made transparent and is used as cermets for glass.
4. Silvered compounds can be absorbed into the circularly system, with deposition of reduced silver in body tissues. This may result in argyria, which is characterized by a greyish pigmentation of the skin and membranes. Silver is germicidal and may be used skin and mucous to kill lower organism without harm to higher organisms.
5. Silver is also used as coinage in many countries.
Sources: Silver occurs native and in ores including argentite and horn silver. Lead, lead zinc, copper, copper-nickel, and gold ores are other principal sources of silver. Commercial fine silver is at least 99.9% pure. Commercial purities of 99.9999% are available.