Giant Ionic Structures
An ionic compound consists of a giant structure of ions arranged in a lattice. There are strong electrostatic forces of attraction between oppositely charged ions, called ionic bonds. This holds the ions in the lattice together very tightly.
It requires a lot of energy to break these ionic bonds, because to seperate the ions we have to overcome the strong electrostatic forces of attraction. This means that ionic compounds have a high mp and bp.
Ionic compounds will often dissolve in water because its lattice can be split up by water molecules. The ions are then free to move around and a solution is formed.
Covalently bonded compounds are made of simple molecules. They have low mp and bp because there are weak intermolecular forces between molecules, and it does not take much energy to overcome these forces.
There is no overall charge on simple molecules such as ethanol, so their molecules can't carry an electric charge. This means that simple…