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Metals - The Reactivity Series

Grade 11IGCSEChemistry

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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The Reactivity Series is an arrangement of metals in order of their reactivity, from most reactive to least reactive: K>Na>Ca>Mg>Al>(C)>Zn>Fe>(H)>Cu>Ag>AuK > Na > Ca > Mg > Al > (C) > Zn > Fe > (H) > Cu > Ag > Au.

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Metals at the top of the series lose electrons more easily to form positive ions (cations): M(s)ightarrowMn+(aq)+ne−M(s) ightarrow M^{n+}(aq) + ne^-.

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A more reactive metal will displace a less reactive metal from its salt solution. For example, ZnZn will displace CuCu from CuSO4CuSO_4.

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Extraction methods depend on position: Metals above Carbon (like AlAl) are extracted via electrolysis of molten ores. Metals below Carbon (like FeFe) are extracted by reduction with Carbon or Carbon Monoxide (COCO).

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Reaction with water: Highly reactive metals (K,Na,CaK, Na, Ca) react with cold water to produce a metal hydroxide and hydrogen gas: 2M(s)+2H2O(l)ightarrow2MOH(aq)+H2(g)2M(s) + 2H_2O(l) ightarrow 2MOH(aq) + H_2(g).

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Reaction with dilute acid: Metals above Hydrogen react with acids (like HClHCl or H2SO4H_2SO_4) to produce a salt and hydrogen gas: M(s)+2HCl(aq)ightarrowMCl2(aq)+H2(g)M(s) + 2HCl(aq) ightarrow MCl_2(aq) + H_2(g).

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Thermal decomposition of carbonates: Carbonates of less reactive metals decompose more easily upon heating. For example, CuCO3(s)ightarrowCuO(s)+CO2(g)CuCO_3(s) ightarrow CuO(s) + CO_2(g), whereas K2CO3K_2CO_3 is thermally stable.

📐Formulae

2Na(s)+2H2O(l)→2NaOH(aq)+H2(g)2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g) (Metal + Water)

Mg(s)+H2SO4(aq)→MgSO4(aq)+H2(g)Mg(s) + H_2SO_4(aq) \rightarrow MgSO_4(aq) + H_2(g) (Metal + Acid)

Fe2O3(s)+3CO(g)→2Fe(l)+3CO2(g)Fe_2O_3(s) + 3CO(g) \rightarrow 2Fe(l) + 3CO_2(g) (Reduction of Iron Oxide)

Zn(s)+CuSO4(aq)→ZnSO4(aq)+Cu(s)Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s) (Displacement Reaction)

2Al2O3→electrolysis4Al+3O22Al_2O_3 \xrightarrow{electrolysis} 4Al + 3O_2 (Extraction of Aluminium)

💡Examples

Problem 1:

Explain why Magnesium reacts with Copper(II) Sulfate solution, but Copper does not react with Magnesium Sulfate solution. Provide the ionic equation.

Solution:

Mg(s)+Cu2+(aq)→Mg2+(aq)+Cu(s)Mg(s) + Cu^{2+}(aq) \rightarrow Mg^{2+}(aq) + Cu(s)

Explanation:

Magnesium is higher in the reactivity series than Copper. Therefore, Magnesium is a stronger reducing agent and can displace Cu2+Cu^{2+} ions from the solution. Copper is less reactive than Magnesium and cannot displace Mg2+Mg^{2+} ions.

Problem 2:

Predict the products when Calcium reacts with cold water and write the balanced chemical equation including state symbols.

Solution:

Ca(s)+2H2O(l)→Ca(OH)2(aq)+H2(g)Ca(s) + 2H_2O(l) \rightarrow Ca(OH)_2(aq) + H_2(g)

Explanation:

Calcium is a reactive alkaline earth metal. It reacts steadily with cold water to form Calcium Hydroxide (limewater) and bubbles of Hydrogen gas.

Problem 3:

In the extraction of Iron in the Blast Furnace, identify the reducing agent and write the equation for the reduction of Haematite (Fe2O3Fe_2O_3).

Solution:

Reducing agent: Carbon Monoxide (COCO). Equation: Fe2O3(s)+3CO(g)→2Fe(l)+3CO2(g)Fe_2O_3(s) + 3CO(g) \rightarrow 2Fe(l) + 3CO_2(g)

Explanation:

In the blast furnace, Coke (CC) reacts with Oxygen to form CO2CO_2, which then reacts with more Coke to form COCO. This COCO reduces the Iron(III) Oxide to molten Iron.

The Reactivity Series - Revision Notes & Key Formulas | IGCSE Grade 11 Chemistry