Compared to most other elements, precious metals are chemically less reactive, have higher melting points, and are more ductile - properties that make them ideal for many commercial and industrial applications. In earlier times, precious metals were mainly used as currency. Today, however, they are highly regarded as investment and industrial commodities. But while platinum is generally resistant to corrosion, it is corroded by certain elements, such as cyanides (potassium cyanide or sodium cyanide), caustic alkalis, sulfur, and any of the five halogens (astatine, bromine, chlorine, fluorine, and iodine). The following lists some of the properties of platinum: General: * Chemical Symbol: Pt * Atomic Number: 78 * Category (as an element): Transition Metal * Group/ Period/ Block (in the Periodic Table): 10/ 6/ d * Atomic Weight: 195.084 g. Cupellation: This technique is considered the most exact, elaborate, and destructive method of assay and is best suited for gold bullion or stock. Also called fire assay, the method involves treating ores or alloyed metals under high temperatures and carefully controlled operations to separate gold from base metals (copper, zinc, or lead), which may be present in the ore. Silver: Silver compounds (example, colloidal silver), when absorbed into the body, may cause argyria, a condition characterized by the bluish-gray pigmentation of the skin, mucous tissues, and the eyes. While the condition is not really harmful to one's health, it is often permanent. Otherwise, silver per se is not at all toxic. These coins contain 90% silver and are 8/10 troy ounce per 1 USD of face value. Buying silver bullion bars: This is the most traditional way of investing in silver. Silver bullion bars can be bought or sold over the counter in most banks in Switzerland. They may be stored in safe deposit boxes in banks or placed in non-fungible (allocated) or pooled (unallocated) storage with a silver dealer. 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.