Learning focus
Develop precise chemical language, connect particle and bonding models to observations, interpret diagrams and data, and apply ideas to unfamiliar examples.
Definition
Metallic bonding is the strong electrostatic attraction between a lattice of positive metal ions and a sea of delocalised electrons. The outer electrons are not attached to one particular atom.
Giant structure
Metal ions are closely packed in a regular giant lattice. The attraction to delocalised electrons acts throughout the structure.
Electrical conduction
When a potential difference is applied, delocalised electrons move through the metal and transfer charge. Metals conduct as solids and liquids because the electrons remain mobile.
Thermal conduction
Mobile electrons and closely packed particles help transfer thermal energy rapidly. This supports the use of metals in cooking vessels and heat exchangers.
Melting point
Metallic attractions must be overcome during melting. Metallic bond strength varies, so metal melting points vary, but many are relatively high.
Practical or data skill
Compare electrical conduction of a metal, graphite, an ionic solid and a molecular solid using a low-voltage circuit.
Examination tip
The positive particles are metal ions, not free protons.
Review questions and suggested answers
Question 1
Define metallic bonding.
Suggested answer
Attraction between positive metal ions and delocalised electrons.
Question 2
What carries charge?
Suggested answer
Delocalised electrons.
Question 3
Do molten metals conduct?
Suggested answer
Yes.
