Gold is a chemical element with the symbol Au (from Latin: aurum) and atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal and a group 11 element. It is one of the few metals that occurs naturally in its pure, elemental (free) form (native gold), as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, such as calaverite and krennerite.
Physics of gold
Density
Gold is one of the densest metals, with a density of 19.3 grams per cubic centimeter. This means that a gold object will have a smaller volume than an object of equal mass made of a less dense material, such as aluminum or copper.
Malleability and ductility
Gold is also very malleable and ductile, meaning that it can be easily hammered into thin sheets or drawn into wires. This is because the gold atoms are arranged in a close-packed cubic crystal structure, which allows them to slide easily past each other.
Electrical conductivity
Gold is an excellent conductor of electricity. This is because the gold atoms have a single valence electron, which is easily freed to move through the metal.
Thermal conductivity
Gold is also a good conductor of heat. This is because the free electrons in the metal can easily transfer heat energy from one atom to another.
Corrosion resistance
Gold is very resistant to corrosion. This is because the gold atoms are tightly bound together and do not react easily with other elements.
Ten question test
- What is the symbol for gold?
- What is the atomic number of gold?
- What is the density of gold?
- What is the crystal structure of gold?
- Why is gold malleable and ductile?
- Why is gold a good conductor of electricity?
- Why is gold a good conductor of heat?
- Why is gold resistant to corrosion?
- What is the most common occurrence of gold in nature?
- What is the most common use of gold today?
Answers
- Au
- 79
- 19.3 grams per cubic centimeter
- Close-packed cubic
- Because the gold atoms are arranged in a close-packed cubic crystal structure, which allows them to slide easily past each other.
- Because the gold atoms have a single valence electron, which is easily freed to move through the metal.
- Because the free electrons in the metal can easily transfer heat energy from one atom to another.
- Because the gold atoms are tightly bound together and do not react easily with other elements.
- Native gold, as nuggets or grains in rocks, in veins and in alluvial deposits.
- In jewelry and other decorative items.
Picture of Gold leaf
Gold leaf is a very thin sheet of gold, typically less than 0.1 micrometers thick. It is made by hammering a gold bar into a thin sheet, which is then cut into small pieces. Gold leaf is often used to decorate objects, such as furniture, picture frames, and religious statues.
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