7.2.2Acids, Bases and Salts
Transition Metals vs Group 1 Metals — Cambridge IGCSE Chemistry 0620 Revision Notes & Topical Questions
5 min read 4 parts Lesson 5 of 11 Unit quiz
Part 1 of 4Key Differences
Transition metals and Group 1 metals are both metals, but they differ in several measurable ways.
Melting point
- Transition metals have higher melting points than Group 1 metals, with mercury as the only common exception.
Density
- Transition metals are denser, and no transition metal floats on water, unlike some Group 1 metals.
Hardness
- Transition metals are stronger and harder, while some Group 1 metals can be cut with a knife.
Reactivity
- Transition metals are much less reactive, so they react far more slowly with water and oxygen.
| Property | Group 1 metals | Transition metals |
|---|---|---|
| Melting point | Low; potassium melts at about 63 °C | High, except mercury |
| Density | Low; some float on water | High; none float |
| Hardness | Soft; some can be cut with a knife | Hard and strong |
| Reactivity | High; react vigorously | Low; iron rusts slowly |
Part 2 of 4Reactions with Air and Water
The difference in reactivity is clearest in how the metals react with oxygen and water.
Reactions with Air and Water
Oxygen
- A Group 1 metal tarnishes quickly in air because it forms a metal oxide layer on its surface.
Rusting
- Iron takes several weeks to rust, and needs both oxygen and water to form hydrated iron(III) oxide.
Water
- Group 1 metals react vigorously with water, while most transition metals do not react with water at room temperature.
Part 3 of 4Writing a Strong Comparison
A good comparison names both groups and uses comparative words.
1
Name both groups clearly so that the comparison is unambiguous.
2
Use comparative words such as higher, denser, harder or less reactive rather than simply describing one group.
3
Support each comparison with a specific example, such as potassium melting at about 63 °C.
4
Check that each statement is accurate for the whole group, allowing for the exception of mercury.
Part 4 of 4Exam Checklist & Tips
7.2.2 – Key Points for the Exam
- Comparative statement A statement that uses words such as higher, harder or less reactive to compare two things.
- Density Mass per unit volume of a substance.
- Reactivity How readily a substance takes part in a chemical reaction.
- Alkali metal Another name for a Group 1 metal.
Common Mistakes
- Writing transition metals are strong instead of stronger; the comparison needs a comparative word.
- Saying all transition metals are liquids; mercury is the only common one that is liquid at room temperature.
- Stating that Group 1 metals are harder than transition metals, which reverses the trend.
- Forgetting that iron rusts slowly only when both water and oxygen are present.
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