Perak

Article

July 6, 2022

Silver is a metallic element with atomic number 47. Its symbol is Ag, from Latin argentum, from the PIE root reconstructed as *h₂erǵ-, "grey" or "shining". A soft, white, and lustrous transition metal, it has the highest electrical conductivity, thermal conductivity and reflectivity of all metals. The metal occurs naturally in its pure, free form (native silver), as alloyed with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of mining copper, gold, lead, and zinc. Silver has long been valued as a precious metal. More abundant than gold, silver metal has functioned in many premodern monetary systems as a species of coin, sometimes even alongside gold. Purity is usually measured on a per-mile basis; 94% pure alloy is described as "0.940 fine". In addition, silver has a wide range of applications beyond currency, such as in solar panels, water filtration, jewelry and ornaments, high value tableware and furniture (the term silverware emerged), as well as investment in coins and bullion. Silver is used industrially in electrical sockets and conductors, in specialty mirrors, window coatings and in the catalysis of chemical reactions. Its compounds are used in photographic film and X-rays. Dilute solutions of silver nitrate and other silver compounds are used as disinfectants and microbicides (oligodynamic effect), added to bandages and wound dressings, catheters and other medical equipment.

Characteristics

Silver is produced during certain types of supernova explosions by the nucleosynthesis of lighter elements via the r-process, a form of nuclear fusion that produces many elements heavier than iron, one of which is silver. than gold), univalent coin metal, polished bright white metallic luster. Protected silver has a higher optical reflectivity than aluminum at wavelengths over ~450 nm. At wavelengths less than 450 nm, the reflectivity of silver falls below that of aluminum and drops drastically to zero at 310 nm. The electrical conductivity of silver is the highest among all metals, even higher than that of copper, but it is not widely used for electrical purposes due to its high cost. tall. An exception to this is in radio frequency engineering, particularly VHF and higher frequencies, where silver plating is done to increase the electrical conductivity of certain parts and wires (at high frequencies current tends to flow on the surface of the conductor, not inside it). , therefore gold plating increases the overall conductivity). Silver also has the lowest contact resistance of all metals. During World War II in the US, 13,540 tonnes were used in the electromagnets used for uranium enrichment, mainly because of the wartime shortage of copper. Pure silver has the highest thermal conductivity of all metals, although nonmetallic carbon in the form of diamond and helium-4 superfluid is more Silver halide is photosensitive and has an amazing ability to record latent images which can then be chemically developed. Silver is stable in pure air and water, but tarnishes when exposed to air or water containing ozone or hydrogen sulfide, the latter forming a black silver sulfide layer, which can be removed with dilute hydrochloric acid. The most common oxidation state of silver is +1 (eg, silver nitrate, AgNO3); less common are +2 compounds (e.g., silver(II) fluoride, AgF2), less common are +3 (e.g., potassium tetrafluoroargentate(III), KAgF4), and even +4 compounds (e.g. potassium hexafluoroargentate( IV), K2AgF6).

Isotopes

Pure natural silver