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Ionic Bonding

Ionic Bonding

  • Ionic bonding is the bond of attraction between METALS and NON- METALS
  • In ionic bonding atoms either lose or gain electrons – this causing them to become charged (ions)
  • When they become charged they then are strongly attracted to each other (because of their opposite charges) – however the overall charge of any ionic compound is zero (because the negative and positive charge cancel each other out).
  • Group 1 & 2 and 6 & 7 are most likely to form ions

 

  • Metals (not counting transition metals) are keen to get rid of their electrons – this is so they can have a full shell left
  • Non – metals, however, are keen to gain electrons to have a full outer shell and become stable
  • When they either gain (non –metals) or lose (metals) electrons then they become ions, as they either have more protons because they lost electrons (metals) so are positively charged, or they have more electrons because they gained them (non-metals) and are negatively charged

 

 

The reaction between sodium and chlorine

In this example where sodium gives up its electron to fill chlorines outer shell, sodium becomes  and chlorine becomes  – it becomes sodium chloride

  • Ionic bonds create a giant ionic structure – called ionic lattices which are regular
  • There are very strong electrostatic forces of attraction between oppositely charged ions – in all directions
  • Ionic compounds all have similar properties
    • They have high melting points and high boiling points – this is because it is hard to break the strong attractions between the ions
    • When ionic compounds melt, the ions are free to move and they carry an electric current
    • However they dissolve easily in the water and they separate
  • When working out the formula of ionic compounds you need to look at the individual ions:
    • g. Sodium Chloride contains and . The (+1) + (-1) = 0 , the charges are balanced with one of each ions, so the formula for sodium chloride = NaCl
    • g. Magnesium chloride contains and  . Because a chloride ion only has one 1- charge, there needs to be two of them to cancel out the 2+ charge of the magnesium ion. This gives the formula .
  • Electronic structure of ions:

 

 

NaCl

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