Melting and boiling are state changes.
The more energy needed, the higher the melting point or boiling point.
There are intermolecular forces between simple molecules. These intermolecular forces are much weaker than the strong covalent bonds in molecules. When simple molecular substances melt or boil, it is these weak intermolecular forces that are overcome. The covalent bonds are not broken. Very little energy is needed to overcome the intermolecular forces, so simple molecular substances usually have low melting and boiling points.
|Substance||Melting point||Boiling point||State at 20°C|
The intermolecular forces between water molecules are stronger than those between oxygen molecules.
A substance can conduct electricity if:
Simple molecules have no overall charge, or charged particles that can separate, so simple molecular substances cannot conduct electricity, even when liquid or dissolved in water.