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How do metals react, and how do we put them in order of reactivity?

Metals: properties and uses, the reactivity series, reactions with oxygen, water and acids, displacement reactions, and oxidation and reduction with ion-electron equations.

An SQA National 5 Chemistry answer on metals, covering their properties and uses, the reactivity series, reactions with oxygen, water and dilute acids, displacement reactions, and oxidation and reduction with ion-electron equations.

Generated by Claude Opus 4.812 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this key area is asking
  2. Properties and uses of metals
  3. The reactivity series
  4. Reactions of metals
  5. Displacement reactions
  6. Oxidation, reduction and ion-electron equations
  7. Worked example: building a redox equation
  8. Examples in context
  9. Try this

What this key area is asking

The SQA wants you to describe the properties and uses of metals, use the reactivity series, write equations for the reactions of metals with oxygen, water and dilute acids, predict and explain displacement reactions, and define oxidation and reduction with ion-electron equations. This key area underpins electrochemical cells and metal extraction.

Properties and uses of metals

The reactivity series

Reactions of metals

Displacement reactions

Oxidation, reduction and ion-electron equations

An ion-electron equation (half-equation) shows one half of the change. For magnesium displacing copper:

Mgβ†’Mg2++2eβˆ’(oxidation)\text{Mg} \rightarrow \text{Mg}^{2+} + 2e^- \quad \text{(oxidation)}

Cu2++2eβˆ’β†’Cu(reduction)\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu} \quad \text{(reduction)}

Worked example: building a redox equation

Examples in context

The reactivity series explains everyday choices. Gold and platinum are found as the pure metal because they are so unreactive, while reactive metals like sodium must be stored under oil to keep them from air and water. Displacement is used in the thermite reaction, where very reactive aluminium displaces iron from iron oxide, releasing so much heat that the iron forms molten, a reaction once used to weld railway tracks. Redox is the basis of batteries and corrosion, both of which appear later in the course.

Try this

Q1. State two typical properties of metals. [2 marks]

  • Cue. Good conductors of electricity and heat; malleable (or ductile, shiny, high melting point).

Q2. Write the ion-electron equation for the oxidation of zinc to zinc ions. [1 mark]

  • Cue. Znβ†’Zn2++2eβˆ’\text{Zn} \rightarrow \text{Zn}^{2+} + 2e^-.

Q3. Explain why magnesium displaces copper from copper sulfate solution. [2 marks]

  • Cue. Magnesium is more reactive, so it takes the place of the less reactive copper, which is deposited as the metal.

Exam-style practice questions

Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

SQA N5 2019 style3 marksMagnesium is more reactive than copper. Predict what would happen if a piece of magnesium were placed in copper sulfate solution, write the ion-electron equation for the oxidation step, and name this type of reaction.
Show worked answer β†’

Markers reward the prediction, the oxidation half-equation, and the reaction type.

Because magnesium is more reactive than copper, the magnesium displaces the copper from the solution: a coating of copper forms on the magnesium and the blue colour of the solution fades.

The magnesium atoms lose electrons, so the oxidation half-equation is:

Mgβ†’Mg2++2eβˆ’\text{Mg} \rightarrow \text{Mg}^{2+} + 2e^-

This is a displacement reaction, and because electrons are transferred it is also a redox reaction (oxidation and reduction happening together).

SQA N5 2021 style3 marksDefine oxidation and reduction in terms of electrons, and write the ion-electron equation for the reduction of copper ions, Cu2+, to copper metal.
Show worked answer β†’

A 3 mark answer needs both definitions and the correct reduction half-equation.

Oxidation is the loss of electrons. Reduction is the gain of electrons. A useful memory aid is OIL RIG: Oxidation Is Loss, Reduction Is Gain.

For copper ions gaining electrons to become copper metal, the reduction half-equation is:

Cu2++2eβˆ’β†’Cu\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}

Each copper ion gains two electrons to become a neutral copper atom, so this is reduction.

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