Properties of metals

Inside a metal

tap a part to see what it explains

This is a tiny window into a lump of metal. The same pattern carries on in every direction, far beyond the edges of the picture: it is a giant structure.

Tap each part of the picture and find out which property it is responsible for.

Where the electrons come from

Calcium is a good one to watch, because each atom gives away two electrons. Tap each part.

Predict, then check

Picture hitting a block of metal hard with a hammer. Commit to an answer before you look.

A metal is hit hard with a hammer. What happens to the layers of positive ions inside it?

What you need to know

• In a pure metal the atoms are arranged in a regular pattern: a giant lattice of positive metal ions in rows and layers.
• Each atom gives its outer shell electron(s) to the structure. These electrons are delocalised: free to move through the whole structure and not tied to any one ion. The number each atom gives matches its ion's charge (sodium gives one and forms Na⁺; calcium gives two and forms Ca²⁺), so the charges balance.
• The metallic bond is the strong electrostatic attraction between the positive metal ions and the delocalised electrons.
• Metals have high melting and boiling points, because a large amount of energy is needed to overcome the strong metallic bonds.
• Metals are malleable and ductile because the layers of ions can slide over each other, and they conduct electricity and heat because the delocalised electrons can move, carrying charge and energy.
• A single metal atom does not have the properties of the bulk metal. The properties come from the atoms bonded together in the giant structure.

The big picture

Inside a metal, the atoms have given their outer shell electrons to the structure and become positive ions, packed in a regular giant lattice of rows and layers. Those electrons are delocalised, free to move through the whole metal, and the strong attraction between them and the positive ions is the metallic bond. That one structure explains the properties: strong bonds give high melting and boiling points, layers of ions that slide make metals malleable and ductile, and moving electrons carry charge and energy, so metals conduct electricity and heat. None of these properties belongs to a single atom; they come from the giant bonded structure.

⚠ Watch out

Saying metals conduct electricity because 'the ions move'. The positive ions stay in their places in the lattice. It is the delocalised electrons that move through the metal and carry the charge.

Memory hook

Hold, slide, flow. The bonds HOLD, so the melting point is high. The layers SLIDE, so metals are malleable and ductile. The electrons FLOW, so metals conduct electricity and heat.

Check yourself

Why does it make no sense to ask whether a single iron atom is a good conductor of electricity?