Bonding

• Ionic bonds

  • When a metal and non metal react together, the metal can lose electrons to form a positively charged ion, whilst the non metal gains electrons to form a negative ion.
  • Strong electrostatic forces of attraction
  • Regular lattice structure
  • Eg. NaCl, MgCl2, K2O
• Ionic compounds

  • High MP and BP due to the strong forces of attraction between ions
  • Do not conduct electricity when solid, but do when liquid as the ions are free to move and will carry an electric charge
  • Dissolve easily in water
• Covalent bonds

  • When a non metal and a non metal combine together and share a pair of electrons
  • Very strong
  • Eg. H2O, CO2, Cl2
• Simple molecular substances

  • Substances with covalent bonds usually have a simple molecular structure
  • This means that they are held together with strong covalent bonds, but the forces of attraction between them are very weak
  • This means they have a low MP and BP
  • Usually gas or liquid at room temperature
  • Don't conduct electricity
• Ionic compounds always have a giant ionic lattice = ions are held together by strong electrostatic forces
• Simple covalent structure = low MP + BP

  Metallic structure = high MP + BP

  Ionic structure = high MP + BP

  Giant covalent structure = high MP + BP