Chemistry · Bonding, Structure and Properties of Matter
Metallic Bonding
Spec 5.2.1.5📗 Foundation
Interactive · electron sea on / off
Theory · read, then commit
Metallic bonding occurs in metals and alloys — a regular lattice of positive metal ions surrounded by a shared sea of delocalised electrons.
1Metal atoms release their outer electrons, which become delocalised — free to move through the whole structure.
2Each atom that lost electrons is now a positive metal ion.
3The positive ions sit in a regular lattice.
4The delocalised electrons move freely between and around the ions — the 'sea of electrons'.
5Strong electrostatic attraction between the positive ions and the electron sea holds the metal together — this IS the metallic bond.
Checkpoint · quick check
Describe the structure of a metal according to the metallic bonding model.
⚠️ Common Mistake
Students often say the metallic bond is an attraction between neighbouring metal atoms. It is not between atoms: the metal atoms lose their outer electrons to become positive ions, and the bond is the strong electrostatic attraction between those positive ions and the surrounding sea of delocalised electrons. That electron sea is also why metals bend rather than shatter — the layers of ions can slide while the sea holds everything together.
🌡️High melting & boiling point
Strong forces between the many positive ions and the electron sea take a lot of energy to overcome.
⚡Conducts electricity
Delocalised electrons are free to move and carry charge through the structure.
🔥Conducts heat
The same delocalised electrons transfer thermal energy rapidly through the metal.
🔨Malleable & ductile
Layers of ions slide and the electron sea re-surrounds them, so metals bend and draw into wires without breaking.
Checkpoint · quick check
Explain why metals are good conductors of electricity.
🧱Example — why alloys are harder
In a pure metal every ion is the same size, so layers slide easily → soft.
An alloy mixes in different-sized atoms that disrupt the regular lattice.
The layers can no longer slide as easily → the alloy is harder and stronger (steel, bronze, brass).