History and Production
Derived from Anglo-Saxon siolfur. The symbol is derived from the Latin argentum, for silver. The metal has been known since ancient time, as one of the coinage metals, probably as early as 3000 BC. Silver can be recovered as a byproduct during the electrolytic refinement of copper.
One of its important use is in photography. It is also used as alloys in dentistry, solder and brazing alloys. Sterling silver, which contains about 92.5% silver, is used to make coins, jewelry and silverware. Silver is also used
in electronic industry for electrical contacts, silver-zinc and silver-cadmium high capacity batteries, and making printed circuit.
It has brilliant white metallic luster in appearance that does not tarnish in air and water when the sulfur content is low. It is
very ductile and malleable and has the highest electrical and thermal conductivity of all metals. Silver occurs (0.08 ppm) as native and in ores mainly as sulfides such as
silver glance (argentite, Ag2S), and also horn silver (AgCl).
Interatomic distance: 289.0 pm
Melting point: 961.78°C
Boiling point: 2162°C
Thermal conductivity/Wm-1K-1: 429 (27°C)
Density/kgm-3: 10500 (20°C), 9345 (m.p.)
Standard Thermodynamic Data (atomic gas)
Enthalpy of formation: 284.9 kJ/mol
Gibbs free energy of formation: 246.0 kJ/mol
Entropy: 173.0 J/mol K
Heat capacity: 20.8 J/mol K
Electronic configuration: [Kr] 4d10 5s1
Term symbol: 2S1/2
Electron affinity: 125.6240 kJ/mol Electronegativity (Pauline): 1.93
Ionization energy (first, second, third): 730.993, 2073.47, 3360.59 kJ/mol
Similar to alkali metals, silver (as well as copper and gold) has only one outer shell s electron. However, it is more tightly
bound to the atom than that of alkali metals because the d electrons has much less shielding effects than that of p electrons. Consequently, silver has much higher
melting point and less reactive than the alkali metal counterpart (rubidium).
Silver is stable in dry air, but in the presence of pollutant such as sulfur dioxide, silver gives the familiar tarnishing effect due to the formation of black silver sulfide.
Test for silver:
(1) Hydrochloric acid or any soluble chloride salt gives a white precipitate, soluble in ammonia and darkens on standing.
(2) Hydrogen sulfide gives a black precipitate.
(3) Potassium chromate gives a brick-red precipitate of silver chromate.