Notes, Exercises, Videos, Tests and Things to Remember on Gold
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Atomic No: 79
Atomic Weight: 197.2
Valency: 1 and 3
Electronic configuration: 1s2,2s2,2p6,3s2,3p6,3d10,4s2,4p6,4d10,4f14,5s2,5p6,5d10,6s1
Position in the periodic table: Gold is a soft, lustrous yellow metal. It is a 'd' block transition element in the periodic table. It belongs to period 6 and group IB.
Gold is a noble metal and has no action with water, air, alkalis and acids. But it dissolves in aqua regia (3:1 ratio of conc. HCl and conc. HNO3) to give gold chloride, nitrosyl chloride and water.
2Au + 3HNO3 + 9HCl → 3NOCl + 6H2O + 2AuCl3
The mixture of conc. Nitric acid and hydrochloric acid in the ratio 1:3 is called aqua-regia. The chemical reaction between conc. Sulphuric acid and silver is: 2Ag + 2H2SO4 → Ag2SO4 + SO2 + 2H2O
Aqua-regia is the mixture of concentrated nitric acid and hydrochloric acid in 1:3 ratio. The chlorine found in aqua-regia can dissolve gold.
When gold is reacted with aqua-regia, gold chloride is formed. 2Au + 3HNO3 + 9HCl → 3NOCl + 6H2O + 2AuCl3
Gold is found in pure state in nature but not the iron because gold is un-reactive metal, so it does not react with other element in normal condition but iron is reactive metal so it reacts with atmospheric oxygen in presence of moist (water) to form oxide.
When gold is heated with chlorine, it gives gold chlorine. 2Au + 3Cl2 → 2AuCl3
The atomic number of gold is ______.
Gold reacts with halogens to form their corresponding ______.