3 - Bonding

• The four types of crystal structure are:

  • Ionic
  • Metallic
  • Macromolecular (giant covalent)
  • Molecular
• Ionic bonding involves electrostatic attraction between oppositely charged ions in a lattice.
• A single covalent bond contains a shared pair of electrons.

  Multiple bonds contain multiple pairs of electrons.
• A coordinate bond (dative covalent) contains a shared pair of electrons with both electrons supplied by one atom.
• Examples of the four types of crystal structure:

  • Diamond
  • Graphite
  • Ice
  • Magnesium
  • Sodium chloride
• Coordinate bonds are represented with an arrow.
• Metallic bonding involves attraction between a sea of delocalised electrons and positive metal ions arranged in a lattice.
• Lone electron pairs decrease bond angles by 2.5 degrees.
• Electronegativity is the ability of an atom to attract the pair of electrons in a covalent bond.
• The three forces between molecules are:

  • Hydrogen bonds
  • Permanent dipole-dipole forces
  • London forces