79AuGold196.96657 u
Gold (Au)
Gold is a transition metal with atomic number 79, in period 6 and group 11 of the periodic table. Its atomic mass is 196.96657 u and its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s¹. Solid at 25 °C.
Key facts
| Atomic number | 79 |
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| Atomic mass | 196.96657 u |
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| Category | Transition Metal |
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| Period | 6 |
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| Group | 11 |
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| Block | d |
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| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s¹ |
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| Electrons per shell | 2, 8, 18, 32, 18, 1 |
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| Electronegativity (Pauling) | 2.54 |
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| Oxidation states | −3, −2, −1, +1, +2, +3, +5common in bold |
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| State at 25 °C | Solid |
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| Melting point | 1337.33 K1064.18 °C |
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| Boiling point | 3129 K2855.85 °C |
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| Density | 19.3 g/cm³ |
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Atomic properties
| First ionization energy | 9.226 eV |
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| Electron affinity | 222.8 kJ/mol |
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| Atomic radius | 144 pm |
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| Covalent radius | 136 pm |
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| Van der Waals radius | 166 pm |
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| Common ions | Au³⁺, Au⁺ |
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| Protons, neutrons, electrons | 79, 118, 79 |
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Physical and thermal properties
| Molar volume | 10.21 cm³/mol |
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| Heat of fusion | 12.5 kJ/mol |
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| Heat of vaporization | 330 kJ/mol |
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| Specific heat | 129.1 J/(kg·K) |
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| Thermal conductivity | 320 W/(m·K) |
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| Thermal expansion | 1.42 × 10⁻⁵ K⁻¹ |
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| Mohs hardness | 2.5 |
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| Young’s modulus | 78 GPa |
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| Crystal structure | Face-centered cubic |
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| Magnetic type | Diamagnetic |
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Identification and history
| CAS number | 7440-57-5 |
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| Latin name | Aurum |
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| Discovered by | Known since antiquity |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 197Au | 196.96657 | 100 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
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Periodic Table