Metallic Bonding

· Metallic bonding = electrostatic attraction between positive metal ions and delocalised electrons.
· Metals contain a regular arrangement of positive metal ions surrounded by a “sea” of delocalised outer-shell electrons.
· Delocalised electrons are not fixed to one atom; they are shared throughout the metallic structure.
· The attraction is between opposite charges: positive ions and negative electrons.
· In exam answers, always include both parts: positive metal ions + delocalised electrons + electrostatic attraction.

This diagram shows metallic bonding as positive metal ions arranged in a lattice with delocalised electrons between them. The key attraction is between the positive ions and the negatively charged electrons. This is the exact idea required for CIE 3.3. Source

Exam Definition

· Full-mark definition: metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons.
· Do not define it as “sharing electrons between atoms” because that sounds like covalent bonding.
· Do not define it only as “a sea of electrons”; that is incomplete without positive metal ions and electrostatic attraction.
· The word delocalised is important: electrons are mobile within the metallic structure, not attached to one specific ion.

Key Exam Words to Use

· Electrostatic attraction
· Positive metal ions
· Delocalised electrons
· Sea of electrons
· Metallic structure
· Outer-shell electrons

Common Mistakes to Avoid

· Do not say metallic bonding is attraction between atoms only.
· Do not forget the word electrostatic.
· Do not forget that the electrons are delocalised.
· Do not describe metallic bonding as ionic bonding; ionic bonding is between oppositely charged ions, not ions and delocalised electrons.
· Do not describe metallic bonding as covalent bonding; covalent bonding involves a shared pair of electrons between nuclei.