C2.2.2

• Define ionic bonding

  the electrostatic attraction between positive and negative ions
• What is shown in the diagram?

  the ionic bonding in potassium fluoride

  
• What is a?

  +

  
• What is b?

  -

  
• What is c?

  electrostatic attraction

  
• How many dots and crosses are in Ks outer shell?

  • dots = 0
  • crosses = 8

  
• How many dots and crosses are in Fs outer shell?

  • dots = 7
  • crosses = 1

  
• In giant ionic lattices each ion attracts oppositely charged ions in all directions with positive and negative ions alternating on each row
• List the properties of ionic compounds:

  • high melting and boiling points
  • soluble in polar solvents
  • conductive as a liquid
  • brittle
• Ionic compounds have high melting and boiling points as a lot of energy is needed to overcome the strong electrostatic attraction between ions . Each ion is held in place by several strong ionic bonds and the bonds are even stronger for greater ionic charges eg 2+
• Ionic compounds are soluble in polar solvents as polar solvents can attract the ions in the compound , surrounding each ion to break the compound down
• Ionic compounds are conductive when liquid or in an aqueous state as the ions can move as mobile charge carriers . In a solid form however the ions are in fixed positions and therefore cannot flow around a circuit to conduct electricity .
• Ionic compounds are brittle as slight movement causes like charges to line up and repel each other , causing the compound to break apart easily .
• What type of structure can be seen in NaCl?

  giant ionic lattice

  
• What is a?

  Na+

  
• What is b?

  Cl-

  
• What is c?

  Na+

  
• What is d?

  Na+

  
• What is e?

  Cl-

  
• What property of giant ionic lattices is shown in the picture?

  Brittle