Year 9 Science · Unit 2 · Lesson 10
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Learning Goals
Compare three
Complete the table to compare ionic, covalent, and metallic bonding. Fill in ALL three compound columns for each feature row.
| Feature | Ionic | Covalent | Metallic |
|---|---|---|---|
| Atoms involved | |||
| How electrons behave | |||
| Typical melting point | |||
| Electrical conductivity | |||
| Malleability | |||
| Example compound |
Read the graph
The graph below shows the relative electrical conductivity of six materials. Study it carefully, then answer the questions.
Data: CRC Handbook of Chemistry and Physics, 105th edition (2024). Values normalised to silver = 100%.
(a) Identify the bond type in each of the six materials shown in the graph.
(b) The graph shows that NaCl solution conducts electricity slightly, but solid NaCl does not conduct at all. Use your knowledge of ionic bonding to explain this difference.
(c) Silver, copper, and aluminium all conduct electricity well, while NaCl solid and polyethylene do not conduct at all. Use bonding theory to explain this pattern.
1. A chemist has an unknown solid. It has a high melting point, is brittle, and conducts electricity when dissolved in water but not as a solid. Using bond-type reasoning, identify the most likely bond type and name one example compound that fits this profile.
2. Aluminium is used to make overhead power lines even though copper is a better conductor. Suggest one reason, based on metallic bonding properties, why aluminium is chosen for this application.
Wrap Up
In one sentence, what was the main idea of this lesson?