Formation of Ions

• Ions


  Charged particles formed when atoms gain or lose electrons
• How ions are formed

  1. Atoms gain or lose electrons

  2. To get a full outer shell like a noble gas

  3. Stable configuration
• Characteristics of ions


  • Long are charged particles
  • Formed when atoms gain or lose electrons
  • To get a full outer shell
  • Full outer shell is very stable
• Noble gases


  • Have a full outer shell
• Metal atoms


  Lose electrons from their outer shell to form positive ions
• Non-metal atoms


  Gain electrons into their outer shell to form negative ions
• Charge of an ion

  Equal to the number of electrons lost or gained
• Ions formed by losing electrons


  • Sodium ion (Na+)
  • Magnesium ion (Mg2+)
• Ions formed by gaining electrons


  • Chloride ion (Cl-)
  • Oxide ion (O2-)
• You can work out what ions are formed by groups 1, 2, 6 and 7 on the periodic table
• Elements in the same group all have the same number of outer electrons, so they form ions with the same charges
• You don't have to remember what ions most elements form, you can just look at the periodic table