Silver (Ag) is a metal, valued since ancient times as a precious metal. This naturally occurring element is a soft, white, lustrous substance. Its classification is based on a unique combination of physical and chemical characteristics rooted in its atomic structure.
Identifying Silver on the Periodic Table
Silver is the chemical element with the symbol Ag and the atomic number 47. Its position on the Periodic Table places it in Period 5 and Group 11, identifying it as a transition metal, alongside copper and gold.
Silver’s metallic identity is linked to its electron arrangement, which features a single electron in the outermost \(5s\) orbital. This lone electron is easily delocalized, meaning it is not tightly bound to a single atom.
The delocalization of this outer electron contributes to the “sea of electrons” that characterizes metallic bonding. This bonding is responsible for the shared physical properties common to all metals. The structure of silver is a face-centered cubic lattice.
The Defining Characteristics of Silver
Silver holds the distinction of having the highest electrical conductivity and the highest thermal conductivity of all known metals. This superior ability to transmit both electric current and heat is a direct consequence of its highly mobile, delocalized \(5s\) electrons.
The metal is known for its brilliant, white, metallic luster, which is a result of its high reflectivity across the visible light spectrum. In its pure form, silver is relatively soft and is exceptionally malleable, meaning it can be hammered into thin sheets. It is also one of the most ductile metals, allowing it to be drawn out into fine, flexible wires.
Chemically, silver is considered a relatively unreactive, or noble, metal, which contributes to its longevity and use in decorative items. It shows strong resistance to oxidation and corrosion from water and pure air. However, silver is susceptible to tarnishing when exposed to sulfur compounds in the atmosphere, which leads to the formation of a thin, black layer of silver sulfide on its surface.
Where Silver’s Metallic Nature Matters
The superior conductivity of silver makes it indispensable in specialized electronic applications where performance is paramount. It is used extensively in electrical contacts, switches, and conductors to ensure reliable, high-efficiency current flow. Its application in solar panels, specifically in photovoltaic cells, relies on this unparalleled conductivity to maximize energy conversion.
The metal’s luster, combined with its malleability and relative non-reactivity, has long made it the standard for jewelry, silverware, and coinage. Sterling silver, an alloy typically containing 92.5% silver, balances the metal’s beauty with the necessary hardness for durability. It is also used in mirrors because of its exceptional reflectivity.
Silver’s metallic form also possesses a unique chemical attribute known as the oligodynamic effect, which gives it antimicrobial properties. This characteristic allows silver ions to interact with and disrupt the function of bacteria and other microorganisms. Consequently, silver is used in medical applications like wound dressings, water purification systems, and certain medical devices to help prevent infection.