Metals and Non-metals

Properties of metals and non-metals, the reactivity series, how ionic compounds form, and how metals are extracted and protected.

Key ideas

Metals are usually lustrous, malleable, ductile and good conductors. Exceptions: mercury is a liquid, sodium and potassium are soft, and graphite (a non-metal) conducts.
Metal oxides are basic; non-metal oxides are acidic; aluminium oxide and zinc oxide are amphoteric (they react with acids and bases).
A more reactive metal displaces a less reactive one from a solution of its salt.
Metals above hydrogen in the reactivity series give hydrogen with dilute acids; copper, silver and gold do not.
Metals give electrons to non-metals to form ionic compounds, which have high melting points and conduct when molten or dissolved, but not as solids.
Extraction: sulphide ores are roasted and carbonate ores calcined to give oxides, which are reduced (by carbon, or by electrolysis for very reactive metals).
Rusting of iron needs both air and water; it is prevented by painting, oiling, galvanising (a zinc coat) or making alloys.

Remember

Reactivity series (most to least)	K, Na, Ca, Mg, Al, Zn, Fe, Pb, [H], Cu, Hg, Ag, Au
Ionic bond	Na → Na⁺ + e⁻; Cl + e⁻ → Cl⁻; together NaCl
Metal + water	2Na + 2H₂O → 2NaOH + H₂

Watch out

Expecting copper to react with dilute hydrochloric acid (it is below hydrogen).
Saying ionic solids conduct electricity (only when molten or in solution).
Calling every metal oxide basic: Al₂O₃ and ZnO are amphoteric.

Worked example

Strips of aluminium are placed in solutions of copper sulphate, lead nitrate, silver nitrate. In which will a reaction take place? Write balanced equations for the reactions.

Working: aluminium displaces only metals below it in the series

Answer: copper sulphate: 2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu; lead nitrate: 2Al + 3Pb(NO₃)₂ → 2Al(NO₃)₃ + 3Pb; silver nitrate: Al + 3AgNO₃ → Al(NO₃)₃ + 3Ag