All practice pages/Interatomic theory/Elements
Element 79, a transition metal
Beautiful, rare and almost indestructible, gold has been treasured for as long as people have made things.
Period 6, group 11. The other transition metals are tinted, and every cell opens its own article.
Gold holds its electrons unusually tightly for a metal, so it resists oxygen, water and nearly all acids. Aqua regia, a mixture of nitric and hydrochloric acids, is one of the few things that dissolves it.
Found mostly as the metal itself, in quartz veins and as grains and nuggets in river gravels, and also in copper ores. China, Australia and Russia mine the most. All the gold ever mined would fit in a cube about 22 meters on a side.
Known since prehistory; gold objects from the Varna burial ground in Bulgaria are more than 6,000 years old. The name is Old English, and the symbol Au comes from its Latin name aurum.
Jewelry takes about half, and investment bars and coins much of the rest. Gold also plates electrical connectors that must never corrode, repairs teeth, and coats astronaut helmet visors and satellite parts to reflect heat. Gold nanoparticles make the colored line on many rapid tests.