General: Chemical Symbol: Ag Atomic Number: 47 Category (as an element): Transition Metal Group/ Period/ Block (in the Periodic Table): 11/ 5/ d Atomic Weight: 107.8682 g.mol-1 Electron Configuration: [Kr] 4d10 5s1 Physical: Density (near room temperature): 10.49 g.cm-3 Liquid Density (at melting point): 9.320 g. Bullion coins minted from platinum include the Manx Noble (minted from 1983 to 1989), the Canadian Platinum Maple Leaf (1988 to 1999), the Australian Platinum Koala (1988 to the present), the Mexican Libertad (1989 only), and the American Platinum Eagle (1997 to the present). The Chinese Platinum Panda were minted in three periods: from 1988 to 1990, 1993 to 1997, and lastly from 2002 to 2005. Of this group of metals, platinum is considered the most widely traded, as it is extensively used in the following: catalytic converters; dental alloys and other dentistry equipment; electrical conductors; resistive thermal devices, laboratory dishes and such other equipment capable of resisting chemical attack even in high temperature; and, of course, jewelry. With an average mass fraction of 0.05 parts-per notation in the continental crust, osmium is known to be one of the least abundant elements in the Earth's crust. It is found in nature in natural alloys or as a pure element. Similar to the other precious metals in the platinum group, osmium can be found in alloys with copper or nickel. Of these four, gold is the most popular. Investing in gold is a way of protecting against crises that may be brought about by economic or political instability or by social unrest. There are at least six ways of investing in gold: Buying gold coins: This is the most popular way of investing in gold. Gold bullion coins are typically priced based on their weight; a premium is added to the gold spot price. In terms of mass abundance, expressed in parts per billion (ppb), here's how the nine precious metals are ranked (rare to rarest): 9th: silver (75 ppb); 8th: palladium (15 ppb); 7th: gold (4 ppb); 6th: osmium (1.5 ppb); 5th to 3rd: iridium, rhodium, and ruthenium (1 ppb); 2nd: rhenium (0.7 ppb); and 1st: platinum (0.003 ppb).