Gold is a chemical element in the Periodic Table represented by the symbol Au, whose atomic number is 79 and belongs to the transition metals.
It is one of the first metals that were manipulated by man, due to the fact that it is found pure in nature.
As a noble metal, gold is one of the most desired metals and widely used in the manufacture of jewelry, coins and ornamental objects in the form of alloy with other metals.
Gold Features
- It has a bright yellow color
- It is corrosion resistant
- Occurs free in nature in the form of nuggets or grains
- Soft and flexible metal
- Little abundant in nature
gold properties
Gold has many applications due to its properties, which go beyond its brightness and color. It is a metal that is easy to work and mold and, therefore, has been used for a long time by man.
Physical properties
| Electric conductivity | 45.2 x 106 S/m |
|---|---|
| Density | 19.3 g/cm3 |
| Toughness | 2.5 (Mohs scale) |
| Fusion point | 1064 °C |
| Boiling point | 2856 °C |
Chemical properties
| electronegativity | 2,54 |
|---|---|
| Ionization energy | 9.226 eV |
| Oxidation numbers (Nox) | +1, +3 |
| Reactivity |
Suffers oxidation:
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| Most common compounds |
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Origin of gold
Due to its characteristics, the records of the exploration of gold by man dates back to 6,000 years. It is possible to see in the Bible the use of gold as a symbol of wealth and Egyptian hieroglyphics date the use of gold from 4000 BC. Ç.
This metal is linked to the culture and history of many peoples as it was discovered by various groups in different places and times.
In antiquity, there are records of gold exploration in Sudan, northern Greece, Iran and China.
In the Middle Ages, in addition to the discovery of this metal in other places, such as Austria and Saxony, the movement called the Alchemy, which sought to transform common metals into high-value materials such as gold.
From the 11th century onwards, it is possible to notice the expansion of this metal around the world, becoming widely used in coins.
Even in America, after its discovery, it was observed that people living in some regions, such as the Incas and Aztecs, they had exploration reserves not only of this metal, but also of silver, which led to the rapid exploitation of the Spanish in the continent.
In Brazil, in the regions of Minas Gerais, Mato Grosso and Goiás gold mines were found, which resulted in a "gold rush" becoming an economic activity in the country's colonial phase.
What is gold for?
Jewelry
The biggest consumption of gold is for jewelry making. Color, shine, durability and the tradition of using this metal make a jewel containing gold valuable.
To increase the strength of the material, artisans prepare an alloy with other metals such as platinum, silver and copper.
Carat was developed to specify the amount of gold in an alloy. For example: 24 carat gold (24K) is pure gold, whereas 12 carat gold (12K) is an alloy in which 50% of its composition belongs to this metal.
Coins
Gold has long had commercial value and is used as a medium of exchange or money. This is due to its rarity, high value and possibility of being fractionated.
The first gold coins were made in 560 BC. Ç. by order of King Croesus of Lydia (a region of present-day Turkey).
There are also gold bars that are still a form of investment by some institutions, due to their ease of handling and storage.
Electronics
Because it is corrosion resistant and has high conductivity, gold is used in electronics that use very low currents and voltages, giving the material reliability.
Sophisticated electronic devices such as cell phones, GPS (Global Positioning System) and calculators have a small amount of gold in their makeup.
Learn more about the periodic table and other chemical elements at:
- Periodic table
- Chemical elements
- Periodic Table Families
- History of the Periodic Table
