Silver
Atomic Data
| Atomic Number | 47 |
| Symbol | Ag |
| Atomic Weight | 107.87 u |
| Density (STP) | 10.49 g/cm³ |
| Melting Point | 961.78 °C (1234.93 K) |
| Boiling Point | 2161.85 °C (2435 K) |
| Electronegativity | 1.93 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1 |
| Oxidation States | +1 |
| Phase at STP | Solid |
| Category | Transition Metal |
| Period / Group | 5 / 11 |
| CAS Number | 7440-22-4 |
Electron Configuration
[Kr] 4d10 5s1
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| O | 5 | 5s | 1 | 47 |
| Total | 47 | 47 | ||
Isotopes of Silver
Silver has two naturally occurring stable isotopes. The most abundant is ¹⁰⁷Ag, comprising 51.839% of all naturally occurring Silver.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Silver-107 | ¹⁰⁷Ag | 47 | 60 | 51.839 | Stable |
| Silver-109 | ¹⁰⁹Ag | 47 | 62 | 48.161 | Stable |
Abundance & Occurrence
Silver is present in Earth's crust at approximately 0.075 ppm by mass and at approximately 0.6 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Universe (ppm by mass)
Discovery & History
Read more about the discovery of the periodic table of elements →
Safety & Handling
- Silver compounds: argyria: Chronic ingestion or skin absorption of colloidal silver or silver salts causes argyria, a permanent blue-grey discolouration of the skin and mucous membranes; colloidal silver supplements have no proven medical benefit and carry real risk.
- Silver nitrate: corrosive: Silver nitrate (AgNO3) is a strong oxidiser and corrosive; contact with skin causes black staining (reduced silver) and chemical burns; eyes require immediate flushing with water if exposed.
- Aquatic toxicity: Silver ions are highly toxic to aquatic organisms at very low concentrations (µg/L range); silver-containing effluents from photography, electronics, and wound dressings must be treated before discharge.
- Silver dust: Fine silver dust is combustible; avoid generating silver dust clouds in the presence of ignition sources.
Silver in the Real World
Real-World Uses
- Electrical contacts and conductors: Silver has the highest electrical conductivity of all metals; silver contacts are used in switches, circuit breakers, relays, and silver-sintered paste forms electrical connections in solar cell busbars and LED modules.
- Photography: Silver halides (AgBr, AgCl, AgI) are the light-sensitive compounds in traditional photographic films and papers; photographic silver demand has declined sharply with the rise of digital imaging.
- Antimicrobial applications: Silver ions and silver nanoparticles kill a broad spectrum of bacteria, fungi, and viruses; used in wound dressings, catheters, water filters, food packaging, and antimicrobial textiles to prevent infection.
- Mirror and solar cell manufacture: Back-silvered glass mirrors and front-surface silver coatings on telescope mirrors exploit silver for its high visible-light reflectance; silver paste electrodes on silicon solar cells collect generated current.
- Jewellery, silverware, and coins: Sterling silver (92.5% Ag, 7.5% Cu) is the standard for jewellery, cutlery, and decorative items; fine silver coins and bars are held as stores of value and traded as investment commodities.
- Brazing alloys: Silver-containing brazing filler metals (Ag-Cu-Zn, Ag-Cu-In) join dissimilar metals and ceramics at temperatures between 600 and 900 °C in plumbing, refrigeration, and precision instrument assembly.
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.
Frequently Asked Questions
What is silver used for?
Silver is used in jewellery, coins, and silverware. Its greatest technical use is in electrical and electronic contacts: silver has the highest electrical and thermal conductivity of any element. Silver is used in photovoltaic solar cells (silver paste in the contact grid), in mirrors (silver's reflectivity is the basis of most glass mirrors), in photography (silver halides are light-sensitive), and in antimicrobial applications in wound dressings and water purification.
Is silver antimicrobial?
Yes, silver ions are toxic to bacteria, fungi, and some viruses. Silver ions interfere with bacterial cell membranes and enzyme function. This antimicrobial property has been used for millennia: ancient civilisations stored water and wine in silver vessels. Today, silver nanoparticles are incorporated into wound dressings, catheters, and surfaces to prevent infection, though concerns exist about resistance development and environmental impact.
How was silver discovered?
Silver has been known and used since at least 4000 BCE, making it one of the metals known to antiquity. Silver artefacts and early silver smelting sites have been found throughout the ancient Middle East. Ancient miners extracted silver from argentite (Ag2S) and other silver ores, and silver quickly became a medium of exchange and symbol of wealth across many civilisations.
Why does silver tarnish?
Silver tarnishes because it reacts with trace amounts of hydrogen sulphide (H2S) and carbonyl sulphide in the atmosphere to form silver sulphide (Ag2S), a black compound. The H2S comes from combustion, industrial processes, and biological decay. Unlike rust on iron, silver sulphide forms a thin surface layer that does not penetrate deeply; it can be removed chemically or by electrochemical reduction using aluminium foil and baking soda.