Silver
Symbol: Ag
Atomic Number: 47
Atomic Mass: 107.8682 amu (atomic mass units)
Melting Point: 961.78 C (1234.93 K, 1763.20F)
Boiling Point: 2162.0 C (2435 K, 3924 F)
Number of Protons: 47
Number of Electrons: 47
Number of Neutrons: 61
Classification: Metal
Crystal Structure: Cubic
Density @ 293 K: 10.501 grams per cubic centimeter
Color: silver
Man has known of the element silver since antiquity. Archaeological evidence shows that man was working with metallic silver over 5000 years ago. The Anglo-Saxon word for silver was “seolfor” and it is from this word that silver gets its name. The symbol “Ag” is derived from the Latin name for silver – “argentum”.
Pure silver metal is the best conductor of both electricity and heat of all the known metals. It tarnishes fairly rapidly in moist air, developing a black coating of silver sulfide. The pure metal is both ductile and malleable. The ionization energy of silver is 7.576 eV and its oxidation state is +1.
Silver has two naturally occurring isotopes both of which are stable. These isotopes, with their natural abundances, are silver-107 (51.839%) and silver-109 (48.161%). The element has number of unstable isotopes, with mass numbers ranging from 93 to 130.
Pure deposits of the silver provide a commercially exploitable source of the metal. It is also extracted from mineral ores such as argentite and silver horn. Some silver is found in conjunction with ore deposits containing gold, lead and copper; silver forms a valuable by-product in the extraction and refining of these metals.
The element and some of its compounds have a number of industrial applications.
* Pure silver and sterling silver are used to make jewelry and other decorative items. Sterling silver is a silver alloy that contains 92.25% silver.
* The electronics industry uses silver in solders, electrical contacts and printed circuit boards.
* Silver is the best-known metallic reflector of visible light. This property makes the element valuable in the production of mirrors. Silvered mirrors require a protective coating to prevent them tarnishing.
* The value of the metal used to be reflected in its usage as a coinage metal. Coins are now made from cheaper metals.
* High capacity batteries are produced using silver in conjunction with either zinc or cadmium.
* The light sensitive compound silver nitrate (AgNO3) forms a coating in the production of .photographic film and paper.
* Silver iodide (AgI) is used to seed clouds to make rain.
* Some silver compounds have an antimicrobial activity. The FDA approves of a number of wound dressings containing silver. Urinary catheters impregnated with silver decrease the incidence of urinary tract infections in patients requiring continual use of indwelling catheterization.
