Properties of Metals (CIE IGCSE Chemistry: Co-ordinated Sciences (Double Award))

• 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
• 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
  • One exception to this is diamond 

• 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 warm or cold, 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)