Silver

Silver is a lustrous, whitish-gray transition metal with the chemical symbol Ag. It has the atomic number 47. This element is unique because it possesses the highest electrical conductivity, thermal conductivity, and reflectivity of any metal.

Because of these physical properties, silver is highly valued in both industrial and economic systems. It is categorized as one of the seven metals of antiquity. This means it has played a fundamental role in human culture for thousands of years. Today, it remains a precious metal often marketed alongside gold and platinum.

The remarkable properties of silver stem from its specific atomic structure. Silver has 47 electrons arranged in a [Kr]4d105s1 configuration. This means it has a completely filled d subshell and a single electron in its highest occupied s subshell.

In its metallic lattice, which is a face-centered cubic structure, only this single 5s electron is delocalized. Because this electron does not interact with the filled d subshell, it moves with extreme mobility. This high mobility is why silver has the highest electrical conductivity of all metals. It also explains why silver has the lowest contact resistance. The thermal conductivity is also among the highest of all known materials, surpassed only by diamond and superfluid helium-4.

Silver is also physically characterized by its extreme ductility and malleability. Ductility is the ability of a metal to be drawn into thin wires. Silver is so ductile that it can be drawn into a wire only one atom wide.

Malleability is the ability to be hammered into thin sheets. While silver is very malleable, it is slightly less so than gold. These physical traits occur because the metallic bonds in silver lack covalent character and are relatively weak. This is due to the filled d-shell, which differs from other transition metals. This unique electron arrangement also gives silver its brilliant white luster. This luster is so distinct that the name of the metal has become a color name.

In nature, silver can be found in several different forms. It exists as native silver, which is the pure, free elemental form found in the Earth's crust. It also appears as an alloy with other metals like gold. Furthermore, it is found within specific minerals such as argentite and chlorargyrite.

Most of the silver used today is not mined directly as a primary metal. Instead, it is produced as a byproduct during the refining of copper, gold, lead, and zinc. This makes silver production closely tied to the mining of these other major metals.

When comparing precious metals, silver is the most abundant of the "big three." These three metals are silver, gold, and platinum. Platinum is the rarest of the group. To put this in perspective, there are approximately 139 troy ounces of silver mined for every one ounce of platinum.

Silver is frequently used for investment and currency. It is sold in the form of bullion, which includes bars and coins.

Because of its high cost, silver is rarely used for general electrical wiring. However, it is essential in radio-frequency engineering. At high frequencies, currents flow on the surface of conductors, making silver plating very effective.

Beyond electronics and money, silver has many diverse applications. It is used in solar panels, water filtration systems, and specialized mirrors. Its high reflectivity makes it superior to aluminum for wavelengths longer than 450 nm. Silver is also a vital component in medicine. Dilute solutions of silver nitrate and other silver compounds act as disinfectants and microbiocides. This is known as the oligodynamic effect. Because of this, silver is added to bandages, wound dressings, and catheters to help control microbes.

It also serves as a colorant in stained glass and is used in specialized confectionery.

Silver is a relatively unreactive metal, which is why alchemists called it a "noble metal." It does not react with air, even when heated to a red heat. However, it can react with sulfur to form black silver sulfide.

This process is known as tarnishing. Silver can also react with salt water to form silver chloride, which appears pale yellow or purplish.

In chemistry, silver most commonly exists in the +1 oxidation state. This state is very stable in both aqueous solutions and solids. This stability is a key reason why silver compounds, especially halides, are so important in scientific processes like gravimetric analysis.