Ionic Bonding: Bond between metal and non-metal with strong electrostatic forces of attraction between oppositely charged ions.
Example of an ionic bond:
Ionic Bonding in Sodium Chloride ( NaCl )
Giant Ionic Lattice: Giant three-dimensional lattice structure held together by the strong attraction between oppositely charged ions.
The lattice structure of Sodium Chloride
Positions of the ions in a crystal of Sodium Chloride
Melting and boiling point of compounds with giant ionic lattices:
- Melting and boiling point depends on the force that holds the particles.
- Giant Ionic Lattices are held together by the strong attraction between oppositely charged ions with many ions and bonds in structure.
- Large amounts of heat energy is needed to overcome forces and break down the bonds.
- Therefore compounds with giant ionic lattices have high melting and boiling points.
- Ionic charge is directly proportional to the melting and boiling point in an ionic compound.
e.g. Magnesium oxide has higher melting point that NaCl. This is because in MgO, 2+ ions are attracting 2- ions and in sodium chloride, the attraction is weaker because there are only 1+ and 1- ions attracted.
Ionic Compounds: Formed when atoms of metals transfer electrons to atoms of non-metals to form compounds made up of ions.
Particles of ionic compounds in solids and when molten or in solution form
Electrical Conductivity of Ionic Compounds:
- Ionic compounds cannot conduct electricity when solid as ions are fixed in structure and are not free to move.
- However, ionic compounds can conduct electricity when molten or in aqueous solution as their ions are free to move to conduct an electric charge.