mol-1 Atomic: Oxidation States: 1, 2, 3 Electronegativity: 1.93 (Pauling scale) Atomic Radius: 144 picometre Covalent Radius: 145 5 picometre Van der Waals Radius: 172 picometre Ionization Energies: 731 kJ.mol-1 (first), 2070 kJ.mol-1 (second), 3361 kJ.mol-1 (third) Despite having higher electrical conductivity than copper, silver isn't as much used for electrical purposes as copper is. These are Australia, Austria, Canada, China, Mexico, Poland, South Africa, Switzerland, the United Kingdom, and the United States. While bullion coins are issued as legal tender, with nominal values assigned to them on minting, such face values are far below the commodity value of the metals themselves. He named it after the asteroid Pallas, which was discovered on March 28 the year before. 3. Osmium - Smithson Tennant, an English chemist, discovered osmium in 1803 from the residues of platinum ores that were dissolved in nitro-hydrochloric acid. Osmium's characteristic of having a bad smell led to its naming as such, which was derived from the Greek word "osme", meaning "smell". While some accounts point to the year 1848 when gold was discovered in California, history tells us that this precious metal was already being used extensively by the ancient Egyptians, Romans, Greeks, Chinese, and South Americans. Throughout history, gold has served as a measure of value and a symbol of wealth. The American Silver Eagle and the Mexican Silver Libertad bullion coins, introduced in 1986 and 1982 respectively, were made of 99.9% silver and 0.1% copper. Other notable silver bullion coins include the Australian Silver Kookaburra, Chinese Silver Panda, and the Russian George the Victorious. Minting coins, whether gold or silver, always entails the risk of having the value of the metal used in the coin greater than the coin's face value. Finally, it was washed with ethanol and reacted with zinc, forming the precious metal that it is known today. Since rhodium occurs in ores mixed with other metals (examples: silver, gold, and platinum), its extraction is complex. For example, it is obtained as a white inert metal from platinum ores, which is quite difficult to fuse.