Knowledge Organiser: Transition Metals
Key Terms
- Transition metals: Central block, centre of periodic table
- Catalyst: Speeds up reaction, not used up
- Variable charge: e.g., Fe²⁺ or Fe³⁺
- Alloy: Metal mixed with other elements
Must-Know Facts
- Hard, dense, high melting point, less reactive than Group 1
- Form coloured compounds: Cu = blue, Fe²⁺ = green, Fe³⁺ = orange-brown
- Can form variable ions (e.g., Fe²⁺ and Fe³⁺)
- Iron: catalyst in Haber process (ammonia)
- Nickel: catalyst for hydrogenation (margarine)
- Platinum: catalyst in catalytic converters
- Alloys harder than pure metals — different-sized atoms disrupt regular layers
- Steel (Fe + C), brass (Cu + Zn), bronze (Cu + Sn)
Key Equations
- No specific equations — transition metals act as catalysts (unchanged in reactions)
- Fe²⁺ + 2OH⁻ → Fe(OH)₂ (green precipitate with NaOH)
- Fe³⁺ + 3OH⁻ → Fe(OH)₃ (orange-brown precipitate with NaOH)
- Cu²⁺ + 2OH⁻ → Cu(OH)₂ (blue precipitate with NaOH)
Common Mistakes
- Saying transition metals are in Groups 1 to 7: They occupy the central block of the periodic table, not the main group columns
- Confusing Fe²⁺ and Fe³⁺ precipitate colours: Fe²⁺ = green; Fe³⁺ = orange-brown — learn both
- Saying catalysts are used up: Catalysts speed up reactions but are not consumed — they remain unchanged
- Forgetting transition metals have variable oxidation states: Iron can be Fe²⁺ or Fe³⁺ — must state which ion in answers
Memory Aid
- The Three C's of Transition Metals: Coloured compounds, Catalysts, Charges that vary (their ions can have different charges, such as Fe²⁺ and Fe³⁺). If you remember the Three C's, you remember all the special properties.
- Catalyst examples: "Iron Haber, Nickel Margarine, Platinum Cars" — iron for the Haber process (making ammonia), nickel for hydrogenation (making margarine/butter), platinum for catalytic converters in cars.
- Compound colours: "Copper Blue, Iron-two Green, Iron-three Orange" — Cu = blue, Fe²⁺ = green, Fe³⁺ = orange/brown. These are the three most tested colour facts.
- Comparing with Group 1: "Transition metals are the OPPOSITE of alkali metals" — hard vs soft, high density vs low, high melting point vs low, less reactive vs highly reactive.