Structure 2.3: Exam Practice
Test your understanding of Metallic Bonding and Alloys.
Part A: Multiple Choice (Mock)
Key Concepts Tested in Paper 1
- Definition: Identifying the description "electrostatic attraction between lattice of cations and delocalized electrons".
- Trends: Predicting that Al > Mg > Na > K for melting point.
- Conductivity: Identifying that functionality relies on mobile electrons, not ions.
Full interactive MCQs coming in future update.
Part B: Structured Questions (Paper 2)
Question 1 Same Period Trend
Explain why Aluminum has a higher melting point than Sodium. (3 marks)
Mark Scheme:
- Aluminum has a higher charge (+3) than Sodium (+1).
- Aluminum contributes more delocalized electrons (3 vs 1) to the "sea".
- Aluminum has a smaller ionic radius.
- Therefore: Stronger electrostatic attraction between cations and delocalized electrons.
Question 2 Properties
Explain, with reference to structure and bonding, why metals are malleable whereas ionic compounds are brittle. (4 marks)
Mark Scheme:
- Metals: Non-directional bonding / "Sea" of electrons moves with the cations.
- Layers of cations can slide over each other without breaking the bond.
- Ionic: Directional electrostatic attraction between fixed ions.
- Sliding layers brings ions of like charge (+/+) together, causing repulsion and shattering.
HL Only
Question 4 Transition Metals
Compare the bonding strength of Calcium and Titanium. Justify your answer. (3 marks)
Mark Scheme:
- Titanium has a stronger metallic bond.
- Titanium is a transition metal and delocalizes both 4s and 3d electrons.
- Calcium only delocalizes 4s electrons (fewer delocalized electrons per atom).