Metallic bonding and metal properties
Use positive metal ions and delocalised electrons to explain electrical and thermal conduction, melting behaviour, malleability and ductility.
On this page
Metallic properties make sense when you connect them to delocalised electrons and the layers of positive ions in the lattice.
Understand metallic bonding
Metallic bonding is the strong electrostatic force of attraction between the positive metal ions and the sea of delocalised electrons.
Key ideas
- Metals have a giant metallic structure: positive ion cores and delocalised electrons throughout the structure.
- Metals conduct electricity because electrons are mobile.
- Many metals are malleable and ductile because layers can move while attraction between positive ion cores and delocalised electrons continues.
- Malleable means able to be hammered into shape; ductile means able to be drawn into wire.
Connect structure to properties
- Positive ion cores attract the delocalised electrons.
- Mobile electrons carry charge through a solid metal.
- Layers can change position while metallic attraction continues.
- The electron population is spread through the whole structure, rather than confined to gaps between layers.
What delocalised means
Delocalised electrons are electrons that are not attached to any one atom. They can move through the whole metal.
Metal atoms’ outer electrons are delocalised through the structure. The remaining positive ion cores occupy lattice positions in a solid metal and attract the delocalised electrons. The whole metal remains electrically neutral.
Swipe or scroll sideways to inspect the complete overview.
Explain the properties of metals
| Property | What you observe | Particle explanation |
|---|---|---|
| Electrical conductivity | Conducts as a solid and when molten | Delocalised electrons are mobile and carry charge |
| Thermal conductivity | Conducts heat well | Mobile electrons transfer energy quickly; vibrations of the lattice also transfer energy |
| High melting/boiling point (most metals) | Usually high | Strong electrostatic attraction between positive ions and delocalised electrons requires lots of energy to overcome |
| Malleable and ductile | Can be hammered / drawn into wires | Layers of positive ions can slide; attraction to delocalised electrons remains so the structure stays together |
Ionic compounds conduct through mobile ions when molten or dissolved. Metals conduct through mobile delocalised electrons. Compare Ionic structures and properties.
What changes when another element is added?
An alloy contains a metal and one or more other elements. Its particles can disrupt the regular arrangement, changing how readily layers move. Continue to Why alloys have different properties to explain those changes and compare particle diagrams.
Misconceptions to check
- Saying metals conduct because “ions move”. In metals, electrons carry charge.
- Treating the positive ion cores as separate noble-gas atoms. Metallic bonding holds the whole structure together through attraction to delocalised electrons.
- Forgetting the sliding-layers explanation for malleability/ductility.
- Treating a general property as a universal rule. Many metals have high melting points, but mercury is liquid at room temperature.
Check the particle explanation
“Strong electrostatic attraction between positive metal ions and delocalised electrons.”
Conducts electricity: “delocalised electrons are mobile”. Malleable/ductile: “layers slide; attraction remains”.
Worked examples
Modelled example 1
Malleability (Sliding Layers)
Problem
Explain why pure metals are malleable.
Study the worked solution
Describe the structure
Method
Identify regular layers of positive metal ions.Reason
Identical ions in a pure metal form an ordered giant metallic structure.
Working
Positive ions are arranged in regular layers surrounded by delocalised electrons.
Apply a force
Method
Allow one ion layer to slide past another.Reason
The layers can change relative position without requiring fixed directional bonds between particular ions.
Working
Force applied → ion layers slide.
Explain why the metal remains together
Method
Retain electrostatic attraction after sliding.Reason
Positive ions remain attracted to the sea of delocalised electrons in their new positions.
Working
The structure changes shape without the metallic bonding being lost.
Guided practice 2
Conductivity (What Carries Charge?)
Problem
Explain why a solid metal conducts electricity.
Identify both the carrier and its mobility
Hints
Hint 1: distinguish metal from ionic conduction
The positive ions remain in lattice positions in a solid metal.
Hint 2: use the definition of delocalised
A delocalised electron is not attached to one atom and can move through the structure.
View solution step by step
Name the charged particles
Method
Identify delocalised electrons.Reason
Outer electrons are shared across the giant metallic structure rather than fixed to individual atoms.
Working
Charge carriers = delocalised electrons.Connect mobility to current
Method
State that the electrons move through the metal.Reason
Moving charged particles transfer charge and produce an electric current.
Working
Mobile delocalised electrons → electrical conduction.
Continue this alloy explanation in Why alloys have different properties.
Continue this alloy explanation in Why alloys have different properties.
Challenge 3
Data Interpretation (Choose the Best Material)
Design transfer
A wire must conduct electricity well while solid and be easily drawn into shape. Choose a metal or an ionic compound and justify both required properties at particle level.
Test both requirements
Hints
Hint 1: test solid conductivity
In a solid ionic lattice, the ions are not mobile.
Hint 2: test shape change
Ductility requires layers to move while the structure remains bonded.
View solution step by step
Choose the material
Method
Select a metal.Reason
A metal satisfies both conductivity and ductility in the solid state.
Working
Choice: metal.Justify conductivity
Method
Use mobile delocalised electrons.Reason
They move through the solid structure and carry charge.
Working
Mobile electrons → solid-state conduction.
Justify ductility
Method
Use sliding ion layers with continued attraction.Reason
Layers can move while positive ions remain attracted to delocalised electrons.
Working
The metal can be drawn into wire without its metallic structure separating.
Try these independently
Compare alloy and pure-metal layers in Why alloys have different properties.
Mind stretcher 1: Conductivity Trap (Molten Ionic vs Solid Metal)Extension
Question: A student says: “Both molten sodium chloride and solid copper conduct electricity for the same reason.” Explain why this is wrong.
Show Answer
Molten NaCl conducts because ions are mobile and carry charge.
Solid copper conducts because delocalised electrons are mobile and carry charge.
Practise and check
See what you know across this topic, then go back to anything you got wrong.
Syllabus and review details
- SEC G3 Pure Chemistry 2027 · 2027
Content structure and subject content, PDF pages 9–24
Last reviewed: