Reactions of Metals and Non-metals: Quick Revision

A brief note on Reactions of Metals and Non-metals. Read it before a test. Try each question at the end before you open its answer.

The reactivity series

K, Na, Ca, Mg, Al, Zn, Fe, Pb, (H), Cu, Hg, Ag, Au, most reactive first.

A metal displaces those below it from their salt solutions.

Oxides

• Metal oxides are basic; aluminium and zinc oxides are amphoteric, reacting with acids and bases.
• Non-metal oxides are mostly acidic: $\text{CO}_2$ gives carbonic acid, $\text{SO}_2$ sulphurous acid. CO and water are neutral.
• Non-metals do not give hydrogen with acids: they gain electrons rather than give them.

A worked example

What volume of hydrogen comes from $2.4\ \text{g}$ of magnesium in plenty of dilute acid? One mole of gas fills about $24\,000\ \text{cm}^3$.

1. Equation. $\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2$.
2. Moles. $\dfrac{2.4\ \text{g}}{24\ \text{g/mol}} = 0.1\ \text{mol}$ of magnesium and of hydrogen.
3. Volume. $0.1 \times 24\,000\ \text{cm}^3 = 2400\ \text{cm}^3$.

Practice with new numbers

A program to try

The program reads the series to predict the reactions of four metals, then works out the worked example.

Mistakes to avoid

• Expecting copper to give hydrogen with acid. It is below hydrogen.
• Reading the series upside down in displacement questions.
• Calling every oxide basic. Non-metal oxides are acidic or neutral, and some metal oxides are amphoteric.
• Expecting hydrogen from nitric acid and most metals. It is an oxidising agent.

Check yourself

1. Which metal reacts with steam but not with hot water: magnesium or iron?

2. Is carbon dioxide an acidic or a basic oxide?

3. Name an amphoteric oxide.

4. Why does gold stay shiny for centuries?