Gold

=Gold=
 * Symbol: Au**
 * Atomic Number: 79**
 * Atomic Mass: 196.96654**

Gold is known as one of the noble metals because of its stability. An attractive and highly valued metal, gold has been known for at least 5500 years. Gold is sometimes found free in nature but it is usually found in conjunction with silver, quartz (SiO2), calcite (CaCO3), lead, tellurium, zinc or copper. There is roughly 1 milligram of gold dissolved in every ton of seawater, although extracting it currently costs more than the gold is worth. It has been estimated that all of the gold that has currently been refined could be placed in a cube measuring 20 meters on a side. Gold is the most malleable and ductile of all known metals. A single ounce of gold can be beaten into a sheet measuring roughly 5 meters on a side. Thin sheets of gold, known as gold leaf, are primarily used in arts and crafts for gilding. One sheet of gold leaf can be as thin as 0.000127 millimeters, or about 400 times thinner than a human hair. Pure gold is soft and is usually alloyed with other metals, such as silver, copper, platinum or palladium, to increase its strength. Gold alloys are used to make jewelry, decorative items, dental fillings and coins. The amount of gold in an alloy is measured with a unit called a carat. One carat is equal to one part in twenty-four, so an 18 carat gold ring contains 18 parts pure gold and 6 parts alloy material. Gold is a good conductor of heat and electricity and does not tarnish when it is exposed to the air, so it can be used to make electrical connectors and printed circuit boards. Gold is also a good reflector of infrared radiation and can be used to help shield spacecraft and skyscrapers from the sun's heat. Gold coated mirrors can be used to make telescopes that are sensitive to infrared light. A radioactive isotope of gold, gold-198, is used for treating cancer. Gold sodium thiosulfate (AuNa3O6S4) is used as a treatment for arthritis. Chlorauric acid (HAuCl4) is used to preserve photographs by replacing the silver atoms present in an image.
 * Atomic Number:** 79
 * Atomic Weight:** 196.966569
 * Melting Point:** 1337.33 K (1064.18°C or 1947.52°F)
 * Boiling Point:** 3129 K (2856°C or 5173°F)
 * Density:** 19.282 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 6 **Group Number:** 11 **Group Name:** none
 * Atomic Radius (pm):** 146
 * Atomic Volume (cc/mol):** 10.2
 * Covalent Radius (pm):** 134
 * Ionic Radius:** 85 (+3e) 137 (+1e)
 * Specific Heat (@20°C J/g mol):** 0.129
 * Fusion Heat (kJ/mol):** 12.68
 * Evaporation Heat (kJ/mol):** ~340
 * Debye Temperature (°K):** 170.00
 * Pauling Negativity Number:** 2.54
 * First Ionizing Energy (kJ/mol):** 889.3
 * Oxidation States:** 3, 1
 * Lattice Structure:** Face-Centered Cubic (FCC)
 * Lattice Constant (Å):** 4.080
 * Specific Gravity (20°C):** 18.88
 * What's in a name?** From the Sanskrit word **Jval** and the Anglo-Saxon word **gold**. Gold's chemical symbol comes from the the latin word for gold, **aurum**.
 * Say what?** Gold is pronounced as **GOLD**.
 * History and Uses:**
 * Estimated Crustal Abundance:** 4×10-3 milligrams per kilogram
 * Estimated Oceanic Abundance:** 4×10-6 milligrams per liter
 * Number of Stable Isotopes:** 1 (View all isotope data)
 * Ionization Energy:** 9.226 eV
 * Oxidation States:** +3, +1

__Where It comes from:__ Gold is found as the free metal and in tellurides. It is widely distributed and almost always associated with pyrite or quartz. Gold is found in veins and in alluvial deposits. Gold occurs in sea water in the amount of 0.1 to 2 mg/ton, depending on the location of the sample.

__Characteristics:__ Gold is a dense, soft, shiny, malleable and ductile metal. Gold is in group 11(transition metal), coinage metal, and period 6 on the periodic table. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Gold has many practical uses in dentistry, electronics, and other fields. It is the most malleable and ductile of all metals.Gold readily creates alloys with many other metals. High quality pure metallic gold is tasteless and scentless, in keeping with its resistance to corrosion.

Gold is bright yellow color and luster which give it its attractiveness. It can be dissolved in aqua regia, as well as alkaline solutions of cyanide, which are used in mining. It has a resistance to corrosion and other chemicals and also has conductivity of electricity which gave it numerous usages . The characteristic oxidation states of gold are +1 (aurous compounds) and +3 (auric compounds). Gold is more easily displaced from solution by reduction than any other metal; even platinum will reduce Au3+ ions to metallic gold. Among the relatively few gold compounds of practical importance are gold chloride, AuCl; gold trichloride, AuCl3; and chlorauric acid, HAuCl4. In the first compound gold is in the +1 oxidation state, and in the latter two, the +3 state. All three compounds are involved in the electrolytic refining of gold. Potassium cyanoaurate is the basis for most gold-plating baths (the solution employed when gold is plated). Several organic compounds of gold have industrial applications. For example, gold mercaptides, which are obtained from sulfurized terpenes, are dissolved in certain organic solutions and used for decorating china and glass articles. __TOXICITY:__ Pure metallic (elemental) gold is non-toxic and non-irritating when ingested and is sometimes used as a food decoration in the form of a gold leaf. Although gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts (gold compounds) by any known chemical process which would be encountered in the human body. Soluble compounds (gold salts) such as gold chloride are toxic to the liver and kidneys. Common cyanide salts of gold such as potassium gold cyanide, used in gold electroplating, are toxic by virtue of both their cyanide and gold content. There are rare cases of lethal gold poisoning from potassium gold cyanide. Gold toxicity can be ameliorated with chelation therapy with an agent such as Dimercaprol.
 * Compounds **

__USES:__ Some of its uses include: currency, jewelry, medicine, food and drink, electronics, and commercial chemistry. It can also be found in alcoholic drinks such as Goldschläger, Gold Strike, and Goldwasser.

Eventhough gold had been found on every continent on earth it is still estimated that 80% of it is still under ground. An ounce of gold can be stretched of 50 miles. Gold has 18 different isotopes.


 * Chemical Symbol: ||  || Au ||
 * Atomic Number: ||  || 79 ||
 * Atomic Weight: ||  || 196.9665 ||
 * Melting Point: ||  || 1064.43 °C ||
 * Boiling Point: ||  || 2850 °C ||
 * Density of Solid: ||  || 19281 kg m-3 ||
 * Electron Configuration: ||  || 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s1 ||

Abundance

 * [|Amount in average human body (70kg):] ||  || 0.01 g ||
 * Average amount in Earth's crust: ||  || 0.004 ppm by mass ||
 * [|Average amount in seawater:] ||  || 0.004 µg L-1 ||

Watch how Gold can be melted:http://youtu.be/aeC7LT4mDm8.

=Price= Like other precious metals, gold is measured by troy weight and by grams. When it is alloyed with other metals the term //carat// or //karat// is used to indicate the purity of gold present, with 24 carats being pure gold and lower ratings proportionally less. The purity of a gold bar or coin can also be expressed as a decimal figure ranging from 0 to 1, known as the millesimal fineness, such as 0.995 being very pure.