Copper in the periodic table, atomic number 29, belongs to the first subgroup. Its nature is as follows:
1. Physical properties
Copper is a rose red metal, soft and metallic luster, with a density of 8.92 g/cm, a dissolution point of 1083.5℃ and a boiling point of 2595℃. It is ductile, easy to bend, and has good strength. In terms of electrical conductivity and thermal conductivity, copper is second only to silver, and it can be processed under hot and cold pressure. Copper and its compounds are non-magnetic. The vapor pressure of copper at the melting point is very small, so it is not volatile at the temperature of the metallurgical process.
2. Chemical properties
Liquid copper can dissolve some gases, such as H2, O2, SO2, CO2, CO and water vapor, etc. The dissolved gases have a certain influence on the mechanical properties and electrical conductivity of copper. Pure copper does not function with dry and wet air at room temperature, but in the wet air of CO2, green film CuCo3Cu (OH)2 will be produced on the surface, also known as verdigren. It ensures that copper will not corrode. When the copper is heated in the air to 185℃, it begins to interact with oxygen, and a layer of dark red copper oxide is formed on the surface. When the temperature is higher than 350℃, the copper color gradually changes from rose color to brass color, and finally becomes black. Copper can be dissolved in nitric acid and oxidant in the presence of sulfuric acid, copper can be dissolved in ammonia, but also with oxygen, halogen and other elements directly combined.