Explain why transition metals are often preferred over Group 1 metals for use in structural and engineering applications.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Engineers selecting materials for bridge construction and industrial machinery must consider properties such as strength, density, and reactivity.
Model answer (5 marks)
Transition metals are preferred because they have much higher melting points than Group 1 metals, so they remain solid under the high temperatures encountered in structural use.
They are also harder and stronger, giving greater resistance to deformation and fracture.
Their densities are higher, allowing a given volume to support larger loads.
Moreover, transition metals are far less reactive; Group 1 metals react violently with water and air, making them unsafe and unsuitable for load‑bearing structures.
Thus, the combination of high melting point, hardness, density and low reactivity makes transition metals ideal for bridges and machinery.
They are also harder and stronger, giving greater resistance to deformation and fracture.
Their densities are higher, allowing a given volume to support larger loads.
Moreover, transition metals are far less reactive; Group 1 metals react violently with water and air, making them unsafe and unsuitable for load‑bearing structures.
Thus, the combination of high melting point, hardness, density and low reactivity makes transition metals ideal for bridges and machinery.
Examiner tips
- Use the word ‘prefer’ and explain each property in turn; link each point to the application (strength, safety).
- Show the order of importance: melting point, hardness, density, reactivity.
- Use the exact terminology: melting point, hardness, density, reactivity.
- Mention the safety issue with Group 1 metals reacting with water/air.
Common mistakes
- Confusing Group 1 metals with transition metals in the answer.
- Omitting the reactivity point or stating it incorrectly.
- Using vague terms like ‘good’ instead of ‘high melting point’ or ‘high density’.
Mark scheme (5 marks)
- Transition metals have higher melting points than Group 1 metals
- Transition metals are harder / stronger than Group 1 metals
- Transition metals are much less reactive than Group 1 metals
- Group 1 metals react vigorously with water (and air), making them unsafe / unsuitable for structural use
- Transition metals have higher densities / are better able to withstand forces, making them suitable for load-bearing structures
Key terms in this question
transition metals · Group 1 metals
Related
- All AQA A-Level Chemistry (7405) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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