Copper, silver and gold are in group 11 of the periodic table, and they share certain attributes: they have one s-orbital electron on top of a filled d-electron shell and are characterized by high ductility and electrical conductivity. The filled d-shells in these elements do not contribute much to the interatomic interactions, which are dominated by the s-electrons through metallic bonds. Unlike metals with incomplete d-shells, metallic bonds in copper are lacking a covalent character and are relatively weak. This explains the low hardness and high ductility of single crystals of copper. At the macroscopic scale, introduction of extended defects to the crystal lattice, such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is usually supplied in a fine-grained polycrystalline form, which has greater strength than monocrystalline forms. COUNT 5
QSN1 What group of the periodic table is copper in? ANS1 group 11 QSN2 Name a property that copper, silver and gold have in common. ANS2 one s-orbital electron QSN3 What makes copper bondings weaker than other metals? ANS3 filled d-electron shell QSN4 How is copper normally supplied? ANS4 fine-grained polycrystalline form QSN5 What is a weaker form of copper than fine-grained polycrystalline? ANS5 monocrystalline forms