Properties of Metals (Cambridge International IGCSE Science)

Physical properties of metals & non-metals

• The Periodic Table contains over 100 different elements

• They can be divided into two broad types:

  • Metals
  • Non-metals

• Most of the elements are metals and a small number of elements display properties of both types

  • These elements are called metalloids or semimetals

The metallic character diminishes moving left to right across the Periodic Table

Properties of metals

• Conduct heat and electricity

  • This is because metals have delocalised electrons that are able to move through the metal structure

• Are malleable (can be hammered and made into different shapes) and ductile (can be drawn into wires)

  • This is because the layers of positive metal ions, in the metal structure, are able to slide over each other

• Usually have high melting and boiling points

  • This is because there is a strong electrostatic attraction between the positive metal ions and delocalised electrons (metallic bond)
  • This strong attraction / bond requires lots of energy to break

Properties of non-metals

• Do not conduct heat and electricity

  • This is because all of the electrons are involved in covalent bonding
  • One exception to this is graphite (it conducts electricity)

• Are brittle when solid and easily break up

  • They are not malleable or ductile
  • One exception to this is graphite

• Low melting and boiling points

  • Many non-metals are gases at room temperature
  • This is because they have weak forces between molecules
  • These weak intermolecular forces do not require a lot of energy to overcome
  • Exceptions to this include diamond

Chemical properties of metals

• The chemistry of metals is studied by analysing their reactions with water, dilute acid and oxygen
• Based on these reactions, a reactivity series of metals can be produced

Reactions of metals with water

• Some metals react with water, either cold water or with steam
• Metals that react with cold water form a metal hydroxide and hydrogen gas

metal + water → metal hydroxide + hydrogen

• For example, calcium:

Ca (s) + 2H₂O (l) → Ca(OH)₂(aq) + H₂(g)

• Metals that react with steam form a metal oxide and hydrogen gas

metal + water → metal oxide + hydrogen

• For example, zinc:

Zn (s) + H₂O (g) → ZnO (s) + H₂(g)

Reactions of metals with acids

• Most metals react with acids, such as HCl
• When acids and metals react, the hydrogen atom in the acid is replaced by the metal atom to produce a salt and hydrogen gas

metal + acid → salt + hydrogen

• For example, iron:

Fe (s) + 2HCl (aq) → FeCl₂(aq) + H₂(g)