Electron Sea Model
Summary: A model of metallic bonding in which positive metal ions sit in a lattice surrounded by a ‘sea’ of delocalised electrons. Tags: igcse chemistry keyword Created: 2026-08-06
The electron sea model (also called the sea of delocalised electrons model) is used to describe metallic bonding. In a metal, each atom loses its outer-shell electrons, becoming a positive ion. These ions are packed in a regular lattice, and the electrons they have lost become delocalised — free to move throughout the whole structure, forming a mobile ‘sea’ of electrons that surrounds the positive ions.
The key IGCSE exam point is that the strong electrostatic attraction between the positive metal ions and the negative electron sea holds the metal together. This model explains the characteristic properties of metals: the delocalised electrons carry charge and thermal energy, so metals are good electrical and thermal conductors; the layers of ions can slide over one another while the electron sea reforms around them, so metals are malleable and ductile; and the strong attraction between ions and electrons means metals generally have high melting points.
Sources
- Cambridge IGCSE Chemistry 0620 Syllabus (2023-2025), Cambridge Assessment International Education
Common Misconceptions
| Misconception | Reality |
|---|---|
| The electron sea refers to electrons shared between pairs of atoms | The electrons are delocalised — not tied to any particular atom or pair — and belong to the whole structure |
| Metallic bonds are attractions between positive ions only | The bond is the electrostatic attraction between positive ions and the sea of delocalised negative electrons |
| The ions in the lattice are free to move about | The positive ions are fixed in their lattice positions; only the delocalised electrons move freely |