Electrical Conductivity: Metals are excellent conductors because the delocalised electrons can move through the lattice when a potential difference is applied. These mobile charge carriers allow for the flow of electric current.
Malleability and Ductility: Metals can be hammered into sheets (malleable) or drawn into wires (ductile) because the layers of positive ions can slide over each other. The 'sea' of electrons adjusts to the new positions of the ions, maintaining the bond even as the shape changes.
High Melting Points: The giant lattice is held together by strong electrostatic forces. Significant thermal energy is required to overcome these attractions and break the regular arrangement of the lattice.
| Feature | Metallic Bonding | Ionic Bonding | Covalent Bonding |
|---|---|---|---|
| Particles | Positive ions & delocalised electrons | Positive & negative ions | Atoms sharing electron pairs |
| Conductivity | High (solid & liquid) | Only when molten/aqueous | Generally low (insulators) |
| Structure | Giant metallic lattice | Giant ionic lattice | Simple molecular or Giant covalent |
| Malleability | Malleable/Ductile | Brittle | Brittle (if giant) |
Use Precise Terminology: Always refer to 'positive ions' or 'cations' and 'delocalised electrons'. Avoid saying 'metal atoms' are attracted to electrons, as the atoms have already lost electrons to become ions.
Explain Conductivity Correctly: Ensure you state that electrons are 'mobile' or 'free to move' to carry charge. Do not confuse this with ionic conductivity, which involves mobile ions.
Link Structure to Property: When asked why a metal has a high melting point, always mention the 'giant lattice' and the 'strong electrostatic attraction' that must be overcome.
Check the State: Remember that metals conduct in both solid and liquid states, which is a key diagnostic test to distinguish them from ionic compounds.
The 'Sea' is not Liquid: Students often mistakenly think the 'sea of electrons' implies the metal is liquid. It is a conceptual model for electron mobility within a solid lattice.
Intermolecular Forces: Never use the term 'intermolecular forces' when discussing metals. Metals are giant structures held by primary chemical bonds, not weak forces between molecules.
Repulsion: Students sometimes forget that while positive ions repel each other, the delocalised electrons sitting between them provide the attractive force that prevents the lattice from flying apart.
