Study Notes
Transition elements are metals known for their high densities, high melting points, and ability to form coloured compounds and act as catalysts. They also have ions with variable oxidation numbers, such as iron(II) and iron(III).
- High Densities — Transition elements are metals characterized by high densities. Example: Densities range from 2 to 22 times greater than water.
- High Melting Points — Transition elements exhibit high melting points compared to other elements. Example: Melting points range from 1000°C to over 3500°C.
- Coloured Compounds — Transition elements are known for forming coloured compounds. Example: Partially filled d-orbitals allow absorption of specific light wavelengths.
- Catalysts — Transition elements and their compounds often act as catalysts. Example: They speed up reactions without being consumed.
- Variable Oxidation Numbers — Transition elements can form ions with different oxidation states. Example: Iron can exist as iron(II) and iron(III) ions.
Exam Tips
Key Definitions to Remember
- High Densities
- High Melting Points
- Coloured Compounds
- Catalysts
- Variable Oxidation Numbers
Common Confusions
- Scandium and zinc are not considered transition elements despite their position on the periodic table.
- Not all metals with high densities are transition elements.
Typical Exam Questions
- What are the characteristics of transition elements? High densities, high melting points, coloured compounds, and catalytic properties.
- How do transition elements act as catalysts? They change oxidation states and facilitate reaction pathways.
- Why do transition elements form coloured compounds? Due to partially filled d-orbitals absorbing specific light wavelengths.
What Examiners Usually Test
- Understanding of transition elements' properties
- Ability to identify examples of variable oxidation numbers
- Knowledge of why certain elements are not considered transition elements