Gold
| Gold
| |
|---|---|
| Symbol | Au |
| Atomic number | 79 |
| Atomic mass | 196.9665 amu |
Gold is named from its Latin name aurum. This element has been known since prehistoric times.
Distinguishing properties
Gold is an inactive metal and it occurs mostly in the uncombined state. It is a soft, malleable metal. It is sometimes found as gold telluride.
Because of its high density, metallic gold can be concentrated by panning. Gold is also recovered from the anode sludge from electrolytic purification of copper. Another method of recovering gold from ores is to form a gold amalgam from which the gold is separated by distilling off the mercury.
Usage
Gold has certain monetary market value. It is also used in jewelery and in dental work. Because of its malleable property, gold can be made into very thin foils which are used in high energy particle physics experiments.
The purity of gold is measured in units of karat. Pure gold is rated at 24 karat. An alloy that is 50% gold is 12 karat. The amount of gold in common jewelry is 18 karat (or 75%).
