Covalent bonds hold atoms together within each simple molecule, but then intermolecularforces hold each molecule to the next.
When simple molecules are heated the covalent bonds remain intact throughout. When the solid simple molecule melts or boils only weakintermolecular forces are broken
Low melting and boiling points
intermolecularforces between the molecules is so weak not much energy is needed to break these forces, so simple molecular compounds have lowmelting points and boiling points
Electrical conductivity
Electricity is a flow of charged particles. Simple molecular compounds do not conduct electricity because they have no charges that can move