Metal repot: Au

Metal report: Gold

Katrina Cymerman

   Gold, an extremely precious metal turns out to have many uses though it is extremely rare to find it in nature at the present moment. The atomic symbol is Au for gold’s original Latin name aurum. Gold, in its natural state, has 79 electrons and 79 protons, and is known as one of the heavier elements on the periodic table due to the fact that the atomic mass is 197 g. Gold has many different uses: jewelry, U.S. coins, electric wiring, and (in a thin foil like form) on different space crafts. Gold has been seen as a precious metal throughout history; from the present to the ancient Egyptians gold has been used to decorate buildings as well as people and as a way to show wealth. Though known as a “noble metal” for its relatively low reactivity, gold is known to combine with different substances to form gold ores and alloys. Gold is mined throughout the world and usually found in its pure form. However, the gold nuggets that were once discovered in rivers to the cries of “Eureka!” are no longer as common because of the extensive demand for gold and the amount of the metal that is being mined each day.

• Characteristics of Gold (Au)
• Color
• Gold is known for its yellow metallic color and its high luster; however, there are some varieties to the color especially when mixed with different metals such as copper and silver, which give gold a reddish tint (rose gold).
• Ductile
• Gold is the most ductile of all the metals because it is also the most malleable of the metals. For example, an ounce of gold can be stretched into 300 square feet of wiring, which makes gold an ideal substance for electrical wiring.
• Malleability
• The malleability of gold makes it possible to be used in extremely thin forms. Some of the thinnest forms of gold are used for food as decorations and some are used for the gold foil in astronauts’ suits to protect them from the harsher conditions in space.
• Electrical conductivity
• Gold is an excellent conductor of electricity and is used in electric wiring due to this fact. However, gold is very pricey so it is not used often in wiring for wiring in peoples’ homes.
• Chemical reactivity
• Though known as a “noble metal” because gold does not react readily with many substances such as air, water, or acids (making it useful for coins and jewelry because it will last long in harsh conditions), yet gold is not completely inert; it reacts readily with a substance called tellurium, though that is not the only mineral is reacts with.
• Uses and applications
• Monetary exchange
• Gold coins are not only a symbol of wealth but are a good investment as the price of gold goes up.
• Gold is too soft to be used in its pure state for anything so it is combined with copper, silver, or other metals in order to harden it. Pure gold is seen as 24 karats.
• Gold standards- total value of money is equal to the amount of gold reserves for a country
• Gold standards were changed during the first world war, which cause inflation and ended all together after the second world war
• Jewelry
• Gold has been used in jewelry throughout history
• However, gold is not used in its pure state and is usually combined with copper to harden it
• Depending on the amount of copper sometimes gold can have a reddish hue to it (rose gold)
• Other times silver is used as an alloy to gold and creates white gold.
• Medicine
• In ancient times people believed that drinking gold was beneficial to health and will lengthen peoples’ lives or maybe even let them live forever.
• Gold as a metallic element is inert to all chemicals in the body and will not cure or help any illnesses; however, gold as a salt can help inflammation and are used to treat arthritis as well as other inflammatory conditions.
• Injectable gold can help treat diseases like tuberculosis
• Food and drink
• Gold foil is used on top of many desserts and is seen as a beautiful decoration to any food.
• Gold is also used in alcoholic drinks known as Goldwasser but gives no taste to the substance.
• Chemistry
• Gold is dissolved in alkaline solutions of potassium or sodium cyanide
• Sodium cyanide is used to extract gold from ores
• Gold’s oxidation forms range from -1 to +5 but Au(I) and Au(III) are most common in chemistry
• History
• Gold was used by the ancient Egyptians in tombs, vases, Funerary masks, and jewelry
• Romans developed ways to extract metal from metal ores and introduced hydraulic mining methods.
• The Aztec people regarded gold as the product of the gods
• Gold has been considered the most sought after metal for centuries
• Since gold has been used for centuries and seems to appear at the same time in many different countries; therefore no exact discovery date has been listed. The probable date of discovery would have been before written documentation.
• Gold was used to decorate palaces and pyramids 
• The metal has been used throughout history in mostly the same way that we use gold today
• Toxicity
• Pure metallic gold is non toxic and can be ingested
• Gold ion is toxic
• Gold chloride can be harmful to livers and kidneys
• Gold poisoning is rare but it can happen and cases of poisoning are usually from potassium gold cyanide
• Gold was voted allergen of the year in 2001  and the allergy to gold is mostly found in women
• Occurance
• Found in ores or in rocks of gold called nuggets
• Sometimes occurs combined with tellurium to form the minerals calaverite, krennerite, magyatite, etc.
• Gold can be found in oceans, rivers, on land in ores or in nuggets
• Production
• Gold is easily mined
• South Africa has been a source for a large quantity of mined gold
• 50% of all gold has been mined from South Africa
• China is now the largest producer of gold in the world
• Other smaller producers are the United states, Australia, Russia, and Peru
• In 2009 estimated that the amount of all the gold ever mined is equal to 165,000 tones with a value of 6.6 trillion dollars
• Isotopes
• There is only one naturally occurring isotope of gold and it is ¹⁹⁷ Au. However, gold does have thirty six radioisotopes with the only stable one being ¹⁹⁵Au with a half life of 186.1 days.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• Interesting facts about gold
• Gold has been recycled ever since it was first discovered; some gold in today’s jewelry is recycled from ancient artifacts and coins
• India is the largest consumer of gold
• Gold film was used in the Astronauts’ (that first landed on the moon) helmets to protect their eyes from the harsh sun.
• Some cars use gold for heat dissipation (scattering)