Delocalised electrons

The electrostatic attraction between those ions and the delocalised electrons holds the structure together. Unlike a covalent shared pair, these electrons are shared across the metal, not between just two atoms.

A piece of metal contains a vast number of particles joined in a giant metallic structure. Its atoms contribute outer electrons to a shared collection of delocalised electrons. The remaining positive metal ions are arranged in regular layers.

In the model of a metal, positive metal ions are packed closely together in a giant structure, surrounded by delocalised electrons that can move through it. The electrostatic attraction between the ions and these electrons is metallic bonding. This arrangement explains the bulk properties of the piece of metal: how it conducts, changes shape and responds to heating.