Copper Properties, Uses and Reactions
Copper is a transition element and it is present in the d-block of the periodic table. Copper belongs to the 4th period so it has 4s orbital and 3d orbital. It is present in the 11th group of the table along with gold and silver. The atomic number of copper is 29 and the mass number is 63.546u. Copper is represented by the symbol Cu. This is derived from the Latin word for copper which is Cuprum.
The electronic configuration of copper is [Ar] 3d10 4s1. Here even though the configuration should be 3d94s2 as the 4s orbital is filled before the 3d orbital. This is to ensure that the 3d orbital is completely filled making it more stable. The 4s orbital should have 2 electrons but it has only one.
So it is half-filled. This also confers some stability.
Copper displays multiple valencies, but it is commonly found as Cu1+ (Cuprous ion) and Cu2+ (Cupric ion). The other oxidation states that it can display are −2,+3 and +4.
Copper has 29 isotopes but the two most stable isotopes are 63Cu (main isotope, 69% of naturally occurring copper) and 65Cu. Copper exists as a face-centered cubic crystalline structure. Copper is generally extracted from its sulfide ores.
The main ores of copper are chalcopyrite (CuFeS2), malachite (CuCO3•Cu (OH) 2), cuprite (Cu2O), chalcocite ( Cu2S), etc.
Properties of copper
Copper has many physical and chemical properties which are quite interesting.
The Physical properties are
Color: Copper is brown to reddish-orange in color. Copper has a bright metallic luster.
State: Copper is solid at room temperature.
Boiling point and the melting point: The copper melts at about 1085°C and the boils at about 2567°C.
A conductor of heat: It is a good conductor of heat and hence used to store water to keep it cool.
An excellent conductor of electricity: Copper has a very electric conducting capacity. Hence, copper is used in making electric wires, fuses, etc.
Copper is a malleable material, can be beaten into sheets.
It can be pulled into wires and is ductile.
Copper has high tensile strength and it can endure heavy loads.
Copper naturally resists deformation.
Copper undergoes a lesser amount of thermal expansion compared to most metals.
Chemical properties of copper:
Copper is a less reactive metal. Copper stands below hydrogen in the reactivity series. So it has less tendency to get oxidized.
Copper gets oxidized when it is exposed to the air for a long time. This layer of copper oxide protects the layer of copper below it. The common oxides formed are Cu2O which is a red powder and CuO which is a black powder.
Copper gets tarnishes when it is exposed to different sulfides and creates different copper sulfides.
Copper does not react with water.
Copper at low temperatures does not react with most dilute acids.
Copper is biostatic which means bacteria does not grow on copper.
Chemical reactions of copper
4Cu + O2 → 2 Cu2O
2 Cu + O2 → 2 CuO (300 to 800 degrees Celsius)
Copper is a comparatively inert metal and has higher reduction potential than hydrogen so pure copper cannot react with non-oxidizing, dilute acids or acids at low temperatures.
Copper reacts with nitric acid and hot concentrated sulfuric acid.
3Cu + 8HNO3 (cold, dilute) → 3 Cu(NO3)2 + 2NO + 4H2O
Cu + 4HNO3 (hot, concentrated) → Cu(NO3)2 + 2NO2 + 2H2O
Cu + 2H2SO4 (hot, concentrated) → CuSO4 + SO2 + 2H2O
Copper reacts with halogens fluorine, F2, chlorine, Cl2, or bromine, Br2,
Cu(s) + F2(g) → CuF2(s) [white color ]
Cu(s) + Cl2(g) → CuCl2(s) [yellow-brown color]
Cu(s) + Br2(g) → CuBr2(s) [black color]
Copper to copper hydroxide
Copper dissolves in nitric acid
Cu (s) + 4 H3O+ (aq) + 2 NO3- (aq) -> [Cu(H2O)6]2 + (aq) + 2 NO2 (g)
Converting to hydroxide[Cu(H2O)6]2+ (aq) + 2 OH- –> Cu(OH)2 (s) + 6 H2O (l)
Uses of copper
Copper is a popular transition metal and it has varied applications in many fields.
Copper is a good conductor of electricity. Copper is used in making electrical connections as it is ductile and can be pulled into wires. It is used to make circuit boards and microchips.
It is used to make welding electrodes, components of microwave ovens, mobile phones, computers, electromagnets, etc.
It also is used to make semiconductors, thermostats and commutator. Thus it is used widely in the telecommunications industry. Copper transformers are more effective.
Due to high conductivity property, copper is used in making wiring in LAN (local area network) systems. It is also used to make components of modems, routers, etc.
Copper is the primary metal used to make many alloys like brass, bronze, German silver, etc. These alloys are used in many fields. Bronze and brass are used to make statues, medals, musical instruments, and sculptures.
Due to the high conductivity of copper, it is used to make copper-indium-gallium-selenide (CIGS) photovoltaic cells. It is also used in heavy amounts to make wind turbines. Copper is also used to make components of motors.
The high thermal conductivity and low thermal expansion of copper make it the ideal material to make cookware and utensils.
Clocks and watches
Copper is non-magnetic and is a suitable material to make components of watches.
It is used to make components of trains, planes, radiators, boats, braking systems, fittings, and fasteners.
Because it is fairly non-corrosive, it is used to make hinges, locks, bathroom fixtures, doorknobs, etc.
It is used to make irrigation and sprinkler systems, condensers in power plants, pipes, piping for seawater and oil.