Structures and Properties
Ionic substances have high melting and boiling points. They conduct electricity when molton or in solution but not when they are solids.
Substances made of simple molecules have low melting and boiling points, this is becuase of their weak intermolecular forces.
The molecules have no charges and therefore do not conduct electricity.
Atoms such as carbon and silicon that form several covalent bonds can form giant covalent structures.