Gold (Au)
Gold (Au) is element 79, a transition metal. Atomic mass 196.96657, configuration [Xe] 4f¹⁴ 5d¹⁰ 6s¹. Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 79 |
|---|---|
| Symbol | Au |
| Standard atomic weight | 196.966570(4) |
| Category | Transition Metal |
| Group | 11 |
| Period | 6 |
| State at room temperature | Solid |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s¹ |
| Valence electrons | 1 (Variable) |
| Common oxidation states | +3 |
| Common ions | No common ions |
| Electronegativity (Pauling) | 2.4 |
| First ionization energy | 890 kJ/mol |
| Electron affinity | 222.7 kJ/mol |
| Atomic radius | 135 pm |
| Density | 19.3 g/cm³ |
| Melting point | 1064.18°C |
| Boiling point | 2856°C |
| Specific heat | 0.129 J/(g·°C) |
Natural isotopes
- Au-197: Stable
Common uses
- Currency/Jewelry
- Electronics plating
- Radiation shielding
Where it matters
- Economics (Gold Standard)
- Electronics (Corrosion-free contacts)
Hazards
- Metallic gold is non-toxic (edible as leaf); some gold compounds are toxic
History
| Discovered | Prehistoric (~6000 BCE) |
|---|---|
| Discovered by | Ancient Civilizations |
| Name | Anglo-Saxon gold (Symbol Au from Latin aurum) |