Properties

• Ionic compounds


  Made of charged particles called ions which form a giant lattice structure
• Ionic substances


  • Have high melting and boiling points due to the presence of strong electrostatic forces acting between the oppositely charged ions
  • These forces act in all directions and a lot of energy is required to overcome them
  • The greater the charge on the ions, the stronger the electrostatic forces and the higher the melting point will be
• Ionic compounds


  • Magnesium oxide (Mg2+ and O2-)
  • Sodium chloride (Na+ and Cl-)
• Ionic compounds are usually solid at room temperature and are non-volatile
• Ionic compounds are usually water soluble as both ionic compounds and water are polar substances
• Ionic compounds are soluble in water


  Because the ions are easily hydrated by polar water molecules
• Electrical conductivity of ionic compounds

  • For electrical current to flow there must be freely moving charged particles such as electrons or ions present
  • Ionic compounds can conduct electricity in the molten state or in solution as they have ions that can move and carry charge
  • They cannot conduct electricity in the solid state as the ions are in fixed positions within the lattice and are unable to move