Metallic bonding and giant structuresEdexcel A-Level Chemistry: Mind map

Exam questions on Metallic bonding and giant structures

1. An electrician is comparing copper wire with a lump of solid sodium chloride as materials for use in a circuit. Copper has a melting temperature of 1085 °C and sodium chloride melts at 801 °C.
   Explain why copper conducts electricity but solid sodium chloride does not.2 marks
2. Graphene is a single layer of carbon atoms arranged in a flat hexagonal pattern. Researchers are investigating it as a conductor for flexible touch screens.
   Explain why graphene conducts electricity whereas diamond does not.2 marks
3. A technician is given four solids, W, X, Y and Z, and records their properties. W melts at 801 °C, dissolves in water, and conducts electricity only when molten or in solution. X is yellow, melts at 115 °C, does not dissolve in water and does not conduct electricity in any state. Y melts at 1085 °C, does not dissolve in water and conducts electricity when solid. Z melts at 1710 °C, is very hard, does not dissolve in water and does not conduct electricity in any state; it contains only silicon and oxygen. X is known to be made of S₈ molecules.
   Deduce the type of structure and bonding in W, in Y and in Z, giving one piece of evidence from the data for each.3 marks