Metallic Bonding and Properties of Metals
Simple Explanation
Metallic bonding is the attraction between positively charged metal ions arranged in a lattice and a "sea" of delocalized valence electrons that are free to move throughout the entire metal, rather than belonging to any one atom.
Why Do We Need It?
This single model explains the whole cluster of properties that make metals so useful: they conduct electricity and heat extremely well, they can be hammered into sheets or drawn into wires without shattering, and they have a characteristic shine.
Why Does This Work?
Because the valence electrons are delocalized (not fixed to any particular metal atom), they are free to flow when a voltage is applied, which is why metals conduct electricity so well. The same freely-moving electrons also let metal ions slide past one another when the metal is bent or hammered without breaking any specific bond (unlike an ionic crystal, where sliding brings like charges together and shatters it) — which is why metals are malleable and ductile rather than brittle.
Real-Life Example
Copper electrical wiring
Copper is used almost everywhere for electrical wiring, and can be drawn into thin, flexible wire.
Copper's delocalized valence electrons let electric current flow through it with very low resistance, and the same 'sea of electrons' lets copper atoms be drawn into thin wires without the metal cracking or breaking.
Practice
Why can a metal be hammered into a flat sheet without shattering, unlike an ionic crystal?
MediumCommon mistake
Describing metallic bonding as just "a type of covalent bonding" — while both involve shared electrons in a loose sense, covalent bonding shares specific electron pairs between specific atoms, while metallic bonding involves electrons delocalized across the entire metal structure, with no fixed pairing to any particular atom.
Quick Review
- Metallic bonding: metal ions in a lattice, held together by delocalized valence electrons.
- Delocalized electrons explain electrical/thermal conductivity.
- The same mobile electrons let metals be malleable and ductile rather than brittle.