Gold has atomic number 79, atomic weight 197, and a density of 19, 30 grams / ml. Gold is resistant to acid, only the king of water that can dissolve it, in which the anion formed tertakloroaurat (III), [AuCl4] -. Golddissolves slowly in potassium cyanide, in which the anion formed disianoaurat (I), [Au (CN) 2] -. Whether in theform of monovalent, or trivalennya, gold can easily be reduced to its metal
     Gold to form various complex compounds, but few simple inorganic compounds. Gold (I) oxide, Au2O, is one of a stable compound with the level of oxidation of +1, as well as copper, +1 oxidation rate is only stable in solid compounds, because of all the gold salt solution (I) have disproportionation into gold and metal ions gold (III) according to the equation:
3Au + (aq) 2Au (s) + Au3 + (aq)
     Gold chemically quite inert so-called precious metals. Gold does not react with oxygen and not corroded in air under normal conditions. But the loose gold in cyanide solution in air pressure. Gold also did not react with any acid or base. However, gold reacts with the halogen and aqua regia
Reaction of gold with the halogen
Gold metal reacts with chlorine, Cl2, or bromine, Br2, to form trihalida gold (III) chloride, AuCl3, or gold (III) bromide, AuBr3.
2Au (s) + 3Cl2 (g) 2AuCl3 (s)
2Au (s) + 3Br2 (g) 2AuBr3 (s)