The periodic table lists 118 known elements as of November 2010. The term "noble metals" refers to an informal, variable grouping of metallic elements in a specific region of the periodic table.
Noble Metals
The group of noble metals traditionally includes the precious metals gold, silver and platinum, as well as the "platinum group" metals (iridium, palladium, rhenium, ruthenium, rhodium and osmium). The noble metals occur close to each other on the periodic table, which is often the case with elements that share basic properties.
Properties
Noble metals are generally unreactive, and tend not to bond easily with other elements. For this reason, they usually occur as metallic ores. They are also resistant to corrosion in acid and oxidation in air.
Uses
Gold, silver and platinum are common in jewelry because of their rarity and beauty. Other noble metals find use in medical and electronic applications, especially when corrosion resistance is necessary; for example, alloys of platinum and osmium are useful in making pacemakers and electrical contacts. Palladium and rhodium are most often found in catalytic converters.
0 comments:
Post a Comment