- Silver (Ag) is a transition metal with atomic number 47, located in Group 11 of the periodic table alongside copper and gold.
- It is a soft, lustrous, white metal renowned for having the highest electrical conductivity, thermal conductivity, and reflectivity of all metals.
- Silver has eleven valence electrons—one in the 5s subshell and ten in the completely filled 4d subshell—and it typically exhibits oxidation states of +1 and, less commonly, +2 and +3. Its atomic structure consists of forty-seven protons, typically sixty-one neutrons, and forty-seven electrons arranged in five shells.
- Naturally occurring silver consists of two stable isotopes: silver-107 (¹⁰⁷Ag) and silver-109 (¹⁰⁹Ag), with ¹⁰⁷Ag being slightly more abundant (51.84%).
- Silver occurs both in its native metallic form and in ores such as argentite (Ag₂S) and chlorargyrite (AgCl). It is often recovered as a byproduct of copper, lead, zinc, and gold refining. Major silver-producing countries include Mexico, Peru, China, Russia, and Australia. Extraction methods depend on the source and may include cyanidation, flotation, amalgamation, or smelting, followed by electrolytic refining for high purity.
- The use of silver dates back thousands of years, with early civilizations valuing it for its beauty, rarity, and workability. Ancient cultures such as the Egyptians, Greeks, and Romans used silver for jewelry, coins, utensils, and decorative art. Silver’s antimicrobial properties were recognized even in antiquity, as it was used to preserve food and water.
- In modern applications, silver plays a vital role in electronics, where its unmatched electrical conductivity makes it essential for high-performance switches, conductors, and contacts. It is also used in soldering alloys, batteries, and photovoltaic cells in solar panels. In the photographic industry, silver halides have been the basis for traditional film photography due to their light sensitivity, although digital technology has largely replaced this use. Silver’s reflective qualities make it valuable for mirrors, coatings on specialized windows, and optical instruments.
- Silver’s antimicrobial and biocidal properties are harnessed in medical applications, including wound dressings, surgical instruments, and coatings for catheters. Nanoparticulate silver is increasingly used in textiles, water purification systems, and consumer products to inhibit bacterial growth.
- Chemically, silver is less reactive than copper but more reactive than gold. It readily forms compounds with halogens, sulfur, and oxygen. Silver nitrate (AgNO₃) is a key laboratory reagent and an important starting material for other silver compounds. Silver sulfide (Ag₂S) is responsible for the tarnish that develops on exposed silver surfaces due to reaction with sulfur-containing gases in the air.
- Biologically, silver is not essential for life and is generally of low toxicity in its metallic form, though prolonged exposure to soluble silver compounds can cause argyria, a condition resulting in bluish-gray skin discoloration.
- From an environmental perspective, silver mining and refining must be carefully managed to prevent contamination from cyanide, mercury, and other chemicals used in extraction processes. Increasingly, silver is recovered from recycling electronics, photographic waste, and other industrial materials, reducing the need for new mining.
