CCEA GCSE Chemistry 2.1 Metals and Reactivity Series Exam Questions

About CCEA GCSE Chemistry 2.1 Metals and Reactivity Series

Metals and Reactivity Series opens Unit 2 of CCEA GCSE Chemistry (Further Chemical Reactions, Rates and Equilibrium, Calculations and Organic Chemistry). You need to place metals in the reactivity series using their reactions with air, cold water and steam, and use the series to predict displacement reactions. The topic explains how the position of a metal relative to carbon decides whether it is extracted by reduction with carbon or by electrolysis, and introduces phytomining. The prescribed practical investigates the reactivity of metals. It links to redox and iron extraction in 2.2 and electrolysis of aluminium in 2.7. Examiners frequently ask for observations, balanced equations and explanations of displacement results.

What you need to know

• Reactivity series Potassium, sodium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver, gold. More reactive metals lose electrons more easily to form positive ions.
• Reactions with water and steam Potassium, sodium and calcium react with cold water to form a hydroxide and hydrogen, for example Ca + 2H2O → Ca(OH)2 + H2. Magnesium, zinc and iron react with steam to form an oxide and hydrogen, for example Mg + H2O → MgO + H2. Copper does not react with water or steam.
• Reactions with air Reactive metals tarnish quickly or burn to form oxides, for example 2Mg + O2 → 2MgO with a bright white light. Less reactive metals such as copper form an oxide layer slowly when heated; gold does not react.
• Displacement A more reactive metal displaces a less reactive metal from a solution of its compound, for example Mg + CuSO4 → MgSO4 + Cu: a pink-brown solid forms and the blue colour fades. The reaction is exothermic.
• Extraction Metals below carbon (such as zinc and iron) are extracted by heating their oxides with carbon (reduction). Metals above carbon (such as aluminium) are extracted by electrolysis, which uses a lot of electricity. Unreactive metals such as gold are found native.
• Phytomining Plants are grown on soil containing low concentrations of metal compounds and absorb them. The plants are burned and the ash contains the metal compound, which is then processed to extract the metal. It is useful for low-grade ores but is slow.

Common mistakes in 2.1 Metals and Reactivity Series

• Writing that metals react with steam to form a hydroxide. With steam they form an oxide and hydrogen.
• Giving the products of a reaction as observations. Describe what you see, such as fizzing or a colour change.
• Placing aluminium below zinc or iron in the series because aluminium seems unreactive. Its protective oxide layer hides its true reactivity.
• Predicting displacement when the free metal is less reactive. Only a more reactive metal can displace a less reactive one.
• Saying that aluminium is extracted with carbon. Aluminium is more reactive than carbon, so electrolysis is needed.

Try three 2.1 Metals and Reactivity Series exam-style questions