* Covalent bonds: In covalent bonds, electrons are shared between atoms. These shared electrons are tightly held within the molecule and are not free to move around.
* Melting: Melting a covalent compound weakens the intermolecular forces, allowing the molecules to move more freely. However, the electrons within the molecules remain bound and are not able to carry an electrical current.
Contrast with Ionic Compounds:
Ionic compounds, on the other hand, are good conductors of electricity when melted. This is because:
* Ionic bonds: In ionic bonds, electrons are transferred from one atom to another, creating positive and negative ions.
* Melting: When an ionic compound melts, the ions become free to move, allowing them to carry an electrical current.
Examples:
* Poor conductors (covalent): Sugar (sucrose), water (H₂O), methane (CH₄)
* Good conductors (ionic): Sodium chloride (NaCl), potassium bromide (KBr), calcium oxide (CaO)
