3.1.3.3 Metallic bonding

• What are metal elements made from?


  Giant metallic lattice structures
• What is metallic bonding?


  Metallic bonding involves electrostatic force of attraction between delocalised electrons and positive ions arranged in a lattice.
• Why do metals have a high melting point?


  Due to the strong electrostatic attraction between the positive metal ions and the delocalised sea of electrons.
• What affects the melting point in metallic bonding?


  The number of delocalised electrons per atom .The more there are, the stronger the bonding will be and the higher the melting point. The size of the metal ion and the lattice structure also affect the melting point.
• Why are metals malleable?


  As no bonds are holding specific ions together, the metal ion layers can slide over each other when the structure is pulled.
• What does malleable mean?

  Can be hammered into shaped
• What does ductile mean?


  Drawn into wires
• Why are metals good conductors of heat?


  The delocalised electrons can pass kinetic energy to each other, making metals good thermal conductors.
• Why are metals good conductors of electricity?


  The delocalised electrons can move and carry a charge.
• Why are metals insoluble?


  Metals are insoluble, except in liquid metals, because of the strength of the metallic bonds.
• What is stronger ionic or metallic bonding?

  ionic
• Why do metals have a high melting point?


  Strong electrostatic forces between positive ions and sea of delocalised electrons require a lot of energy to break
• How do the number of protons affect metallic bonding? 


  More protons= stronger bond
• How does the number of delocalised electrons affect metallic bonding?


  More delocalised electrons= stronger bond
• How does the size of the ion affect metallic bonding?


  Smaller ion= stronger bond
• How does the charge of an ion affect melting point? 


  Higher charge = higher melting point
• Describe the bonding in magnesium

  Attraction between (lattice of) Mg2+ ions And delocalised electrons
• Explain why magnesium has a higher melting point than sodium.

  Mg2+  has a higher charge than Na+

  Attracts delocalised electrons more strongly 
• Use your knowledge of structure and bonding to explain why sodium bromide has a melting point that is higher than that of sodium, and higher than that of sodium iodide.


  Stage 1 - Na1a) Metallic bonding1b) Attraction between the + nucleus and delocalised electrons 1c) Na- giant lattice structure

  Stage 2 – NaBr / NaI2a) Ionic bonding 2b) Attraction between the + and – ions

  2c) Giant lattice structure

  Stage 2 - bonding3a) Ionic bonds are stronger than metallic bonds

  3b) Stronger attraction between the + and – ions in NaBr than in NaI

  3c)since the Br– ion is smaller than the I– ion
• Suggest why titanium can be hammered into different shapes.


  Layers of atoms (over one another)
• Suggest why these objects with different shapes have similar strengths.

  (Strong) (metallic) bonding/ same (metallic) bonding / bond strength
• Diamond is able to scratch almost all other substances, whereas graphite may be used as a lubricant. Diamond and graphite both have high melting points. Explain why in terms of structure and bonding. 


  • Both macromolecular
  • C atoms in diamond joined to 4 other C atoms
  • C atoms in graphite joined to 3 other C atoms
  • diamond hard because of 3-D structure
  • Graphite soft as layers can slide (weak) van der Waals’ forces
  • Melting point
  • covalent bonds must be broken which are strong / hard to break;
  • Other differenceDiamond is non-conductor of electricity, graphite is conductor