The symbol Au is commonly used to represent gold on the periodic table of elements. But what does the Au actually stand for and where does it come from? Let’s take a closer look at the origins and meaning behind the chemical symbol for gold.
The History Behind Au as the Symbol for Gold
The use of Au as the atomic symbol for gold can be traced back to the Latin name for the metal, aurum. Aurum means “shining dawn” or “glow of sunrise.” This name was used by the ancient Romans and has origins before that in older languages. The word aurum was adapted from aurum as an abbreviated symbol when elements began to be represented by one or two letters.
In the early 1800s, English chemist and physicist John Dalton published his ideas about atomic theory and proposed representing each chemical element with a symbol. Dalton chose the first letter or first two letters of the element’s name in English or Latin. For gold, this became Au from aurum.
Dalton’s symbols were adopted and standardized in chemistry. Au has been used to represent gold ever since on the periodic table and in chemical equations and formulas. While the name aurum fell out of common usage, its legacy remains in the Au symbol every chemist recognizes.
Why Au Stuck as the Symbol for Gold
Once Dalton established Au as the atomic symbol for gold in 1808, it quickly caught on and became the standard designation. There are a few key reasons why Au has endured as gold’s chemical symbol for over 200 years:
- Dalton’s atomic theory and proposition of elemental symbols was widely accepted and applied throughout chemistry at the time.
- Au follows the conventions set by Dalton – one or two letters based on the Latin or English name.
- The symbol Au maintains ties to gold’s history through the Latin aurum meaning shining dawn.
- Au is distinct and not easily confused with symbols for other elements. For example, the first letter G is already used for germanium.
- There was no reason or impetus to change the established Au symbol which already worked well to represent gold.
In other words, Au fit the guidelines, was quickly adopted, and no superior symbol presented itself. Chemists agreeing on standard atomic symbols like Au also helped unify chemistry research and understanding around the world.
Properties of the Element Gold
Now that we know where Au comes from, let’s examine some key properties of the element it represents – gold:
- Gold atomic number: 79
- Gold atomic weight: 196.967 amu
- Gold symbol: Au
- Gold group: transition metal
- Gold period: 6
- Gold electrons: 79
- Gold protons: 79
- Gold neutrons: 118
- Gold melting point: 1064.18°C
- Gold boiling point: 2807°C
- Gold density: 19.32 g/cm3
Gold is a dense, soft, shiny metal with a bright yellow color. It is highly unreactive and resistant to corrosion and tarnishing. Gold is a good conductor of electricity and heat. It is also ductile and malleable, meaning it can be drawn into thin wires or pounded into thin sheets.
Interestingly, gold is one of the few elements that is not white or gray in its pure form. Its attractive golden hue helped lead to its historical and modern value and use for coins, jewelry, and more.
Occurrence and Origin of Gold
Gold can be found across the world, but the main sources are in South Africa, China, Australia, Russia, and the United States. Significant gold deposits are often formed near volcanoes and mountain ranges. This is because gold is propelled upward during volcanic eruptions and then solidifies in rocky veins.
Gold ore is mined from these deposits and then isolated through various chemical processing methods. Earth’s gold is believed to have been created by the r-process (rapid neutron capture) supernova nucleosynthesis. When a large star collapses, it releases a tremendous amount of neutrons that combine with heavy elements like gold during the explosion.
The r-process is responsible for generating about half the abundances of elements heavier than iron. This includes naturally forming gold here on Earth as well as across the universe during star formation.
Uses of Gold Throughout History
Gold has been used and valued extensively throughout human history. Some key uses include:
- Jewelry and Art: Gold has been crafted into decorative art, jewelry, and adornments since at least 4000 BC.
- Coins: Gold coins were minted and used by many ancient civilizations. The first known gold coins date back to 550 BC in Asia Minor.
- Medicine: Gold was historically thought to have healing properties, although modern medicine has debunked this. Some gold salts do have anti-inflammatory effects.
- Religious Objects: Gold gilding and decoration feature prominently on statues, temples, tombs, and other religious artifacts.
- Dentistry: Gold has been used for dental fillings since antiquity and is still sometimes used today, although other materials like resin are now more common.
- Electronics: Because it is highly conductive, corrosion-resistant, and durable, gold is used in some electronics like connectors.
- Aerospace: Gold reflective coatings on astronaut helmets, space satellites, and spacecraft help control temperature.
While jewelry and financial purposes account for most of gold’s modern uses, its unique properties continue to make it valuable for select industrial and technological applications as well.
Gold Supply and Production
Only around 190,000 tonnes of gold have been mined throughout history, according to GFMS Gold Survey data. This amount would form a cube about 21 meters on a side. Here is an overview of current gold supplies worldwide:
| Source of Gold Supply | Tonnes |
|---|---|
| Jewelry recycling | 1,304 |
| Mine production | 3,380 |
| Gold bars | 1,276 |
| Official coins | 314 |
| Medals & imitations | 92 |
| Dental & industrial | 56 |
| Total | 6,422 |
In 2021, around 3400 tonnes of gold were mined globally. The leading producers were China, Russia, Australia, and the United States. Since 1950, global gold production has increased steadily in a ramp up phase, leveling off starting around the year 2000.
However, finding new sources of gold is increasingly difficult. Most major gold deposits near the surface have already been exhausted. Gold production must shift to lower quality sources that require more complex mining and extraction processes. This makes gold harder and more expensive to source over time.
Gold Prices and Trading
Gold prices are primarily driven by supply and demand. Because new gold is rarely found in large quantities, prices tend to rise over time as demand grows faster than available supplies from mining. Gold prices can be volatile, however, moving both up and down based on investor activity and external economic factors.
Some key gold trading details:
- Gold is traded 24 hours a day globally on financial markets.
- Common trading units are troy ounces, grams, and kilograms.
- Gold is commonly alloyed with copper and silver to increase durability for jewelry and coins.
- Karats measure gold purity – 24K is pure gold, 18K is 75% gold, etc.
- Common investment vehicles are bullion, bars, coins, jewelry, futures contracts, ETFs, and gold mining stocks.
The price of gold reached record highs above $2000 per ounce in 2020, but had declined to around $1750 by early 2023. Gold remains an attractive investment for hedging during times of economic uncertainty and inflation.
Key Properties of Gold in Review
To summarize gold’s defining characteristics that make it useful across so many applications and lend it inherent value:
- Dense and malleable for forming jewelry and decorative objects
- Excellent conductor of heat and electricity
- Resistant to corrosion and most chemicals
- Rare and increasingly difficult to source
- Unique shiny yellow appearance
Together, these traits make gold one of the most versatile, functional, and coveted metals – represented aptly by its elemental symbol Au.
Conclusion
The chemical symbol Au has been used to represent gold since 1808 when John Dalton first proposed it based on the Latin word aurum. Despite changes in naming conventions and language, Au has endured as gold’s atomic symbol for over 200 years because it succinctly captures the essence of this special element.
From its origins in Latin to its modern applications, Au signifies gold in contexts ranging from ancient coinage to electron microscopy to asteroid mining. The Au symbol neatly encapsulates gold’s history, properties, and importance – affirming why it remains the standard designation for element 79 on the periodic table.