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Properties of MetalsOxford AQA IGCSE Chemistry: Revision notes

Section 1

What physical properties do metals share?

Most metals share a set of physical properties that make them useful in construction, wiring and cookware:

  • Good conductors of heat and electricity
  • Malleable — can be hammered or pressed into shape without breaking
  • Ductile — can be drawn out into wires
  • High melting and boiling points (with a few exceptions, e.g. mercury)
  • Lustrous (shiny) when freshly cut or polished
  • Generally high density
  • Sonorous — produce a ringing sound when struck
Key termsmalleableductilelustrous

Section 2

Why are metals good conductors of heat and electricity?

Metals are giant structures of positive metal ions surrounded by a 'sea' of delocalised electrons — electrons that are not attached to any one atom and are free to move throughout the whole structure.

  • Electrical conductivity: the delocalised electrons carry electrical charge through the metal when a voltage is applied
  • Thermal conductivity: the delocalised electrons transfer kinetic energy quickly through the structure, and the closely packed ions also vibrate and pass energy to their neighbours
Key termsdelocalised electrons
Exam tip

In exams, always link 'good conductor' explanations back to delocalised electrons being 'free to move' — this is the marking point examiners look for.

Section 3

Why can metals be bent and hammered into shape?

Metals are malleable and ductile because of how their atoms are arranged and bonded:

  1. Metal atoms are arranged in regular layers within the giant metallic structure
  2. Metallic bonding is strong but not directional — each positive ion is attracted equally to the surrounding sea of electrons, not to one specific neighbour
  3. When a force is applied, the layers of atoms can slide over each other into a new position
  4. The delocalised electrons continue to hold the structure together as the layers move, so the metal bends or changes shape rather than shattering
Key termslayers of atoms
Common mistake

Students often confuse 'malleable' with 'strong'. A metal can be strong (hard to break) and still malleable (easy to reshape) — these describe different properties.

Section 4

How does metallic bonding explain these properties?

Metallic bonding is the strong electrostatic attraction between the positive metal ions and the delocalised (negative) electrons surrounding them, acting in all directions through the lattice.

PropertyExplanation
Conducts electricitydelocalised electrons carry charge
Conducts heatdelocalised electrons and vibrating ions transfer energy
Malleable/ductilelayers of ions slide without breaking the bonding
High melting pointstrong electrostatic attraction needs lots of energy to overcome
Key termsmetallic bonding

Must Know

  • Metals are good conductors of heat and electricity
  • Metals are malleable (can be hammered) and ductile (can be drawn into wire)
  • Conductivity is explained by delocalised electrons being free to move
  • Malleability is explained by layers of atoms sliding over each other
  • Metallic bonding is the strong electrostatic attraction between positive ions and delocalised electrons, acting in all directions
  • Metallic bonding is non-directional, which is why metals deform rather than shatter

That's the notes covered.

Carry on to the next subtopic.