The Element Copper
Introduction to the Element Copper
The element copper is a metal element that belongs to Group 11 on the periodic table. It is known for its malleability, conductivity of heat & electricity, and high ductility. These properties make it a commonly-used element in industrial products. Copper is found in nature, and has been used for thousands of years. It is named after its Latin name, cuprum.
Copper in the Periodic Table
The element copper has symbol Cu and atomic number 29. Copper is a transition metal at the top of group 11 on the periodic table, along with silver and gold. However, all of the elements in group 11 have quite distinct chemical properties. Like silver and gold, copper has a very rich aqueous chemistry.
Copper is located in the d-block and its electron configuration is [Ar]4s13d10. It lies to the right of nickel and the left of zinc on the periodic table.
Fun Facts About Copper
- Copper has antimicrobial properties. Copper surfaces protect against transfers of the SARS-CoV-2 virus.
- There are more than 570 copper alloys; the 2 most well-known copper alloy families are brasses and bronzes.
- The word “copper” comes from its original description as Cyprium aes, meaning “metal from Cyprus”.
- Pennies were originally made from pure copper; however, they are now about 97.5% zinc with only a thin copper covering.
- The Statue of Liberty gets its green color from its copper coating oxidizing.
- The element copper has extremely high conductance of both heat and electricity.
- Copper is essential to all living organisms because it is a key component of a respiratory enzyme complex
- Pure copper has a reddish-orange color, one of the only metals not to be silvery or gray
- Copper powder can easily be made by adding aluminum foil and a dash of salt to a copper sulfate solution
- Copper acetate can easily be made at home by adding copper to a mixture of vinegar and 3% hydrogen peroxide
- Pennies in the USA went from being mostly copper, to being mostly zinc in 1982.
Copper’s Antimicrobial Properties
In 2008, the Environmental Protection Agency (EPA) named copper the first antimicrobial metal. Furthermore, the organization listed 300 copper surfaces as antimicrobial. The term “contact killing” was coined for the process of microbes being inactivated on copper surfaces. According to Professor Cassandra D. Salgado, this occurs as the element “interferes with the electrical charge of the organisms’ cell membranes.” Researchers have observed that the effectiveness of contact killing increases with increased copper content (in alloys), increased temperature, and increased relative humidity.
Copper’s Applications in Today’s World
What is copper used for?
Copper has various industrial applications because of its metallic properties. Some of these products include rods and bars, wires, pipes, and tubes. Copper alloys have many properties such as corrosion resistance and biofouling resistance; these make copper suitable and effective for many uses, such as in marine environments.
Copper is also essential for the human body. We need about a milligram of copper each day. Copper is used in coins in most countries
History of the Element Copper
Let’s talk about who discovered copper. Copper was one of the first elements used by man, with copper artifacts dating back to 9000 BC. In the early ages, humans used copper in tools and for decorative purposes because of its malleability and durability. So to be honest, no one knows who “discovered” copper.
Early Romans named copper aes Cyprium, meaning “metal from Cyprus,” because they were able to mine copper in large quantities in Cyprus. The name was eventually shortened to cuprium in Latin, which became “copper” in English.
Copper Chemistry – Reactions & Compounds
Corrosion – Copper Oxidation
Copper metal reacts with the air and water (moisture in the air) to form copper carbonate.
2Cu + O2 + CO2 + H2O → CuCO3 + Cu(OH)2
So what is happening here? Over time, copper metal will oxidize in air and lose its luster. Copper forms copper (I) oxide and then copper (II) oxide, which then turns into copper basic carbonate. This greenish layer is called a patina, and is best seen on the statue of liberty. There is a nice explanation here. If there is pollution in the air (e.g. sulfur dioxide), then copper sulfide and basic copper sulfate will also form as part of the patina.
Copper + Oxygen
Heated copper metal at high temperatures can react with oxygen to form copper(II) oxide (CuO). Then, the copper(II) oxide can react with hydrogen gas at high temperatures to form copper metal and water.
2Cu + O2 → 2CuO
CuO + H2 → Cu + H2O
Copper (II) oxide, a black powder, can also be formed by the decomposition of copper (II) nitrate, carbonate or hydroxide. When freshly produced, it readily reacts with acids to form the corresponding copper (II) salt.
Copper (I) oxide, Cu2O is yellow or red, depending on the particle size. It is found in nature as the mineral cuprite. It can be formed via the slow oxidation of copper, or via the reduction of a copper (II) solution with a mild reducing agent. Copper(I) oxide is the product of the Fehling’s test and Benedict’s test which test for reducing sugars. Reducing sugars will reduce an basic solution of a copper(II) salt, producing a bright red precipitate of Cu2O.
Copper + Water & Acids
The element copper does not react with water; this makes it suitable for use in industrial products such as pipes. Copper does not visibly react with hydrochloric, sulfuric, or acetic acid. However, adding hydrogen peroxide will cause the copper to react, often forming a mix of copper(I) and copper(II) salts.
Copper reacts vigorously with concentrated nitric acid, creating the poisonous nitrogen dioxide gas. With dilute nitric acid, the less toxic NO is produced.
Fluorine: Cu + F2 → CuF2
Chlorine: Cu + Cl2 → CuCl2
Bromine: Cu + Br2 → CuBr2
Copper (II) iodide is not stable, and instead a combination of elemental copper and white copper (I) iodide is usually produced. The other copper halides are more stable.
Copper usually forms compounds known as copper(II) salts, which are blue-green in color in solution. These salts are also water-soluble and can be poisonous in large amounts. Many living organisms have trace amounts of the compounds as essential nutrients. The blue color of copper in aqueous solution is due to the formation of the hexaaquacopper(II) ion, Cu(H2O)62+.
Copper(II) sulfate is an inorganic compound with the formula CuSO4. In its pentahydrate form, the compound is a bright blue salt that dissolves in water in an exothermic reaction and decomposes into the anhydrous form before melting.
Anhydrous copper(II) sulfate is a white solid that forms from the dehydration of copper(II) sulfate pentahydrate. Many tests also use copper(II) sulfate is as an analytical reagent.
Isolation of Copper
Adding a more reactive metal to a copper compound solution can easily isolate copper. For example, you can make copper powder from aluminum foil, or copper crystals from a piece of zinc. In the video below, we make copper powder
Additionally, copper nanoparticles have been synthesized using the chemical reduction approach. In the experiment, copper(II) sulfate pentahydrate solution, starch, ascorbic acid, and sodium hydroxide solution are combined and heated. Once it cools, researchers filter out the precipitates from the final solution.
ChemTalk Video showing how to isolate elemental copper
Copper Oxidation States
Copper exists in +1 and +2 oxidation states, known as the cuprous ion (Cu+) and cupric ion (Cu+2), and much more rarely in the +3 oxidation state. The cupric ion, copper (II), is the most common and stable.
Physical Properties of Copper
- Symbol: Cu
- Melting point: 1084.62oC
- Boiling point: 2595oC
- Density: 8.96 g/cm3
- Atomic weight: 20.180u
- Atomic number: 10
- Electronegativity: 1.90
- Classification: transition metal
- Natural abundance of copper in the earth’s crust: 0.0068%
- Electron shell configuration: [Ar]4s13d10
- Isotopes: copper-63, copper-65
- Found naturally in the minerals: azurite, malachite, chalcocite, acanthite, chalcopyrite, bornite
- Toxicity: large amounts of copper can be toxic
Where Can I Buy Copper?
You can easily purchase copper online from stores that sell metals!