Transition Metals — AQA GCSE Chemistry (Separate)
The transition metals are found in the central block of the periodic table and have properties typical of metals plus some special features.
Position and general properties
The transition metals sit in the middle block of the periodic table (between Groups 2 and 3). Like all metals, they are hard, strong, shiny and good conductors of heat and electricity.
Compared with Group 1 metals, transition metals are:
- harder and stronger,
- have higher melting points (except mercury),
- have higher densities, and
- are much less reactive (they react slowly or not at all with water and oxygen).
Special properties
Transition metals have features that Group 1 metals do not:
- They can form ions with different charges (variable valency), e.g. iron forms Fe²⁺ and Fe³⁺.
- They form coloured compounds (e.g. copper compounds are blue, iron(II) is green, iron(III) is orange-brown).
- They are useful as catalysts (e.g. iron in the Haber process, nickel in hydrogenation).
Comparison with Group 1
| Group 1 | Transition metals | |
|---|---|---|
| Hardness | soft | hard |
| Melting point | low | high |
| Reactivity | very reactive | much less reactive |
| Ion charges | always +1 | variable |
| Compounds | white/colourless | coloured |
Exam tips
- Transition metals are in the central block.
- Learn their special properties: variable ion charges, coloured compounds, catalysts.
- They are harder, denser, higher melting and less reactive than Group 1 metals.
- Give examples (iron Fe²⁺/Fe³⁺; copper compounds blue; iron as a catalyst).