Copper is relative inexpensive metal and widely used since old civilization. It is an excellent conductor of heat and electricity. Copper resist corrosion and is widely used in making various alloys.
Discovery and History
Copper has been known from prehistoric times and Neolithic humans used copper as stones as early as 8000 BCE. Copper was the first metal that was smelted from ores in 5000 BC and later used in pottery in North Africa. Early societies used it in place of gold and silver for making decorative items and ornaments . Later, bronze which is an alloy of copper and tin was introduced between 3500 to 2500 BC in West Asia and Europe. In the Temple of King Sa’H-Re in Abusir, copper tubes for conveying water were used in 2750 BC. The name copper has been originated from Cyprium, which is Latin for metal of Cyprus. The term copper was introduced for the first time in 1530. The symbol of copper is Cu, derived from cuprum.
|Periodic Table Classification||Group 11
|State at 20C||Solid|
|Color||Red-orange metallic luster
|Electron Configuration||[Ar] 3d10 4s1|
|Electron Shell||2, 8, 18, 1|
|Density||8.96 g.cm-3 at 20°C|
|Atomic Mass||63.55 g.mol -1|
|Electronegativity according to Pauling||1.90|
Copper is widely present in many parts of world in combined state and free state. In combined form it exit as chalcocite (sulfide mineral), chalcopyrite (copper +iron sulfide), bornite (copper+ iron ore), cuprite (oxide mineral), malachite (copper carbonate) and azurite (copper carbonate) . It is also present in the ashes of sea weeds and in sea corals. Copper is also present in human liver. In invertebrates it is present in many mollusks and arthropods. Andes Mountains in Chile is the greatest known deposit of copper mineral. Other major producers are Peru, China and the United States. Commercially copper is produced through smelting, followed by electrodeposition from sulfate solutions.
Fresh Copper has pinkish color but soon convert into reddish orange color due to direct exposure with oxygen. Copper oxidizes in the air and exhibit green color that’s why roof of building looks green. Copper is flexible and soft due to which it can be stretched into wires easily . Copper dissolve in a mixture of hydrogen peroxide and hydrochloric acid to form copper chloride. Copper’s atomic number is 29 and its atomic mass is 63.54g/mol. Its melting point is 1083oC and boiling point is 2595oC. Copper is very dense in nature its density at 20oC is 8.9 g/cm3. Copper is biostatic in nature that means no bacteria and other forms of life can grow on it. Various alloys of copper also have antimicrobial properties.
Copper has low chemical activity, it slowly reacts with oxygen and form a layer of brown black copper oxide that protects the underlying metal from further corrosion. Copper compound exist in two oxidation state +1 and +2. +2 compounds are blue in color. +1 compounds are white in color. They are weak oxidizing agent. Copper (I) compounds are weak reducing agents they react with air and make copper (II) compounds. They are not dissolve in water. Copper (II) are stable in air than copper(I) compounds. Gases are soluble in molten copper helpful in mechanical and electrical properties of solidified metal. Copper forms many alloys by mixing with other metals, most common alloys are brass and bronze.
Copper has 29 isotopes 63Cu and 65Cu are stable in nature. Other isotopes are radioactive in nature, 67Cu has half-life 61.83 hours.
Uses and significance
- Copper is frequently used in wires, as it is an excellent conductor of electricity .
- Copper has been used in making sculpture, it was also used in the construction of Statue of Liberty.
- Copper is also used in photographic techniques.
- Copper is used as fungicide in agriculture.
- Copper is very important in countless types of electrical equipment.
- Electrical devices rely on copper wiring due to its inherent properties.
- Copper is corrosion resistant and present in weatherproof architectural materials.
- Various alloys of copper are widely used in making jewelry.
- Copper is used in textile industry for making of antimicrobial protective fabrics.
- In past, copper chloride has been used to treat fever, arthritis and sciatica.
U.S recommended dose of copper is about 1.4 to 2.1mg per kg body mass.
Copper is helpful in facilitating iron uptake that’s why its deficiency can lead to anemia. Too much copper in diet also cause various problems. Human get copper mostly in the form of food and vitamin supplements. Various genetic disorders can affect the ability of body to use copper properly. Intake of copper is helpful to prevent cardiovascular diseases and osteoporosis. Copper enables body to make red blood cells.