Metallic Bonding

Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons.

Metallic bonds are formed when atoms in a metal lose electrons from their outer shell, becoming positive ions.
These free electrons form a ‘sea’ of delocalised electrons that surrounds the positive ions.

Malleability and Ductility: Metals are malleable (can be hammered into shape) and ductile (can be drawn into wires) because the layers of ions can slide over each other without breaking the bond.
Conductivity: Metals are good conductors of both heat and electricity because the delocalised electrons can move freely and transfer energy.
Melting and Boiling Points: Metals generally have high melting and boiling points due to the strength of the metallic bonding.

The structure of a metal is a lattice arrangement of ions in fixed positions.
Between these ions, there is a ‘sea’ of delocalised electrons which can move freely.
This ‘sea’ of electrons gives rise to many characteristic metallic properties, including lustre and electrical conductivity.

Alloys are mixtures of two or more elements, at least one of which is a metal.
The properties of an alloy can be very different from its constituent elements.
The different sized atoms in an alloy disturb the regular arrangements of ions, making it harder for layers to slide over each other and strengthening the material.

Metals occupy the left and centre parts of the Periodic Table.
As you move across a period from left to right, the strength of metallic bonding increases up to Group 4, then decreases.
As you go down a group in the Periodic Table, the strength of the metallic bonds generally decreases. This is due to the increasing size of the ions and the greater number of energy levels between the nucleus and the delocalised electrons.