Periodic Table
79
Au
196.97
Gold
Transition MetalConfig exception (5d¹⁰6s¹); dissolves only in aqua regia; relativistic colour.
Electronic Configuration
[Xe] 4f¹⁴ 5d¹⁰ 6s¹or1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 5d¹⁰ 6s¹
Electron shells
2e⁻n=1
8e⁻n=2
18e⁻n=3
32e⁻n=4
18e⁻n=5
1e⁻n=6
Properties
Atomic number
79
Atomic mass
196.97 u
Category
Transition Metal
Block / Group / Period
d · 11 · 6
Valence electrons
1
Oxidation states
+1, +3
Electronegativity
2.54
Atomic radius
174 pm
Ionization energy
890 kJ/mol
Electron affinity
223 kJ/mol
Melting point
1337 K / 1064 °C
Boiling point
3129 K / 2856 °C
Density
19.282 g/cm³
State at 25 °C
solid
JEE / NEET notes
- Electronic config exception: [Xe]4f¹⁴5d¹⁰6s¹.
- Dissolves only in aqua regia (3 HCl : 1 HNO₃) → HAuCl₄.
- Yellow colour from relativistic effects on 5d→6s transition.
- Most malleable and ductile metal.
Exceptions
- • 5d¹⁰6s¹ configuration; relativistic colour.
Ores & extraction
Ores: Native gold, Calaverite
Extraction: Cyanide leaching (Mac-Arthur Forrest process).
Uses
Jewellery · Electronics · Currency reserves · Dentistry
Important compounds
HAuCl₄AuCl₃
Personal Notes
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