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79 platinum ← gold → mercury Ag ↑ Au ↓ Rg Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	gold, Au, 79
Chemical series	transition metals
Group, Period, Block	11, 6, d
Appearance	metallic yellow
Standard atomic weight	196.966569(4)  g·mol−1
Electron configuration	[Xe] 4f14 5d10 6s1
Electrons per shell	2, 8, 18, 32, 18, 1
Physical properties
Phase	solid
Density (near r.t.)	19.3  g·cm−3
Liquid density at m.p.	17.31  g·cm−3
Melting point	1337.33 K (1064.18 °C, 1947.52 °F)
Boiling point	3129 K (2856 °C, 5173 °F)
Heat of fusion	12.55  kJ·mol−1
Heat of vaporization	324  kJ·mol−1
Specific heat capacity	(25 °C) 25.418  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 1646 1814 2021 2281 2620 3078
Atomic properties
Crystal structure	cubic face centered
Oxidation states	−1, 1, 2, 3, 4, 5 (amphoteric oxide)
Electronegativity	2.54 (Pauling scale)
Ionization energies	1st: 890.1 kJ/mol
	2nd: 1980 kJ/mol
Atomic radius	135  pm
Atomic radius (calc.)	174  pm
Covalent radius	144  pm
Van der Waals radius	166 pm
Miscellaneous
Magnetic ordering	diamagnetic
Electrical resistivity	(20 °C) 22.14 n Ω·m
Thermal conductivity	(300 K) 318  W·m−1·K−1
Thermal expansion	(25 °C) 14.2  µm·m−1·K−1
Speed of sound (thin rod)	(r.t.) (hard-drawn) 2030  m·s−1
Young's modulus	78  GPa
Tensile Strain	0.00157
Shear modulus	27  GPa
Bulk modulus	220  GPa
Poisson ratio	0.44
Mohs hardness	2.5
Vickers hardness	216  MPa
Brinell hardness	? 2450  MPa
CAS registry number	7440-57-5
Selected isotopes
Main article: Isotopes of gold iso NA half-life DM DE (MeV) DP 195Au syn 186.10 d ε 0.227 195Pt 196Au syn 6.183 d ε 1.506 196Pt β- 0.686 196Hg 197Au 100% 197Au is stable with 118 neutrons 198Au syn 2.69517 d β- 1.372 198Hg 199Au syn 3.169 d β- 0.453 199Hg
References

Gold (pronounced /ˈɡoʊld/) is a chemical element with the symbol Au (from its Latin name aurum) and atomic number 79. It is a highly sought-after precious metal which, for many centuries, has been used as money, a store of value and in jewelry. The metal occurs as nuggets or grains in rocks, underground "veins" and in alluvial deposits. It is one of the coinage metals. Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold has a bright yellow color traditionally considered attractive.

Gold formed the basis for the gold standard used before the collapse of the Bretton Woods system. The ISO currency code of gold bullion is XAU.

Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion.

Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. Gold does not react with most chemicals, but is attacked by chlorine, fluorine, aqua regia and cyanide. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Gold is insoluble in nitric acid, which will dissolve silver and base metals, and this is the basis of the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test," referring to a gold standard test for genuine value.