2.1.5Atomic Structure and the Periodic Table
Metallic Bonding
5 min read 4 parts Lesson 1 of 10 Unit quiz
Section 1 of 4The Metallic Structure
A metal is a giant structure in which the outer electrons of its atoms are free to move.
Giant lattice
- Metals are giant structures of atoms arranged in a regular pattern.
Metal ions
- Each atom loses its outer electrons and becomes a positive metal ion that stays in a fixed position.
Delocalised electrons
- Outer electrons that no longer belong to any one atom and move freely between the metal ions, forming a sea of electrons.
Metallic bond
- The strong electrostatic attraction between the positive metal ions and the delocalised electrons.
Section 2 of 4Metals and Alloys
The structure of pure metals and alloys explains their properties.
1
In a pure metal, layers of ions can slide over one another while the delocalised electrons remain free to move.
2
Because the electrons move freely, metals conduct electricity and heat very well.
3
An alloy is a mixture of a metal with other elements, and the different-sized atoms disrupt the regular layers.
4
This disruption makes alloys harder and stronger than pure metals, which is why alloys are useful for construction.
Section 3 of 4Comparing the Three Bond Types
Each type of bonding handles outer electrons in a different way.
Comparing the Three Bond Types
Ionic
- Electrons are transferred from metal atoms to non-metal atoms, which forms charged ions.
Covalent
- Electrons are shared in pairs between two non-metal atoms, forming molecules or giant structures.
Metallic
- Electrons are delocalised, not transferred or shared between specific pairs of atoms.
Conductivity
- Metals conduct because delocalised electrons carry charge through the structure, while solid ionic compounds do not.
| Feature | Ionic | Covalent | Metallic |
|---|---|---|---|
| Particles | Ions | Atoms or molecules | Metal ions and electrons |
| Electrons | Transferred | Shared | Delocalised |
| Typical structure | Giant lattice | Simple molecules or giant covalent | Giant lattice |
| Conducts when solid? | No | No | Yes |
Section 4 of 4Exam Checklist & Tips
2.1.5 – Key Points for the Exam
- Metallic bond The strong attraction between positive metal ions and the delocalised electrons around them.
- Delocalised electron An outer electron that is free to move throughout a metal rather than belonging to one atom.
- Alloy A mixture of a metal with one or more other elements.
- Giant metallic lattice A regular arrangement of metal ions in a sea of delocalised electrons.
Common Mistakes
- Saying that metal electrons are transferred to specific atoms, as in ionic bonding;
- they are delocalised instead.
- Describing metallic bonding as covalent sharing between two atoms;
- the electrons are shared across the whole metal.
- Saying that alloys are pure metals; an alloy is a mixture of a metal with other elements.
- Explaining the conductivity of metals as the movement of ions;
- it is the delocalised electrons that carry the charge.