science

• Metals


  • Hard
  • High boiling points
• Explanation for hardness and high boiling points

  Strong electrostatic forces between metal cations (+) and delocalised electrons (-)
• Metals


  • Have free moving charged particles: the delocalised electrons
  • Solid metals conduct electricity
• Explanation for electrical conductivity

  Delocalised electrons can move towards a positive electrode, resulting in current
• Metals


  • Malleable and ductile
• Explanation for malleability and ductility


  When a force causes metal ions to move, layers of ions remain held together by the delocalised electrons between them
• Metals


  • Have lustre
  • Have high density
• Explanation for lustre


  The delocalised electrons in a metal lattice reflect light
• Explanation for high density

  Metal cations are closely packed
• Metals


  • Have good heat conductivity
• Explanation for good heat conductivity

  Closely packed metal cations can transmit kinetic energy along the lattice via vibration
• Metals


  • React by losing electrons
• Explanation for reactivity


  Due to the low electronegativity of metals, the valence electrons are easily removed
• The metallic bonding model is the most widely used model for explaining the properties of metals, but there are other more sophisticated models that can be used to explain unusual properties
• The metallic bonding model cannot explain differences in electrical conductivity, the magnetism of cobalt, iron and nickel, differences in the hardness of metals, and the different densities of metals
• The metallic bonding model also cannot explain boiling and melting points
• Homework: Complete worksheet 3