Transition Elements (CIE IGCSE Chemistry)

• Transition elements are found in the centre of the Periodic Table between Group 2 and Group 3
• Most metals are transition elements and have properties typical of a metal:
  • They are lustrous
  • They are hard and strong
  • They conduct heat and electricity
  • They have high melting points
    • Except mercury: This has a low melting point which is why it is a liquid at room temperature

The transition elements in the Periodic Table

Transition elements are found in the middle of the Periodic Table

• There are some properties that are only typical of transition elements :
  •  They form ions with different charges
    • E.g. Iron forms Fe²⁺ and Fe³⁺ ions
  • They are useful as catalysts
    • E.g. Iron is used as the catalyst in the Haber process

• • They form coloured compounds 

    • E.g. Copper forms blue copper sulfate, black copper oxide and green copper carbonate

Coloured compounds formed by transition metal ions

The colours produced by some transition elements ions

Extended tier only 

• The transition elements have more than one oxidation number, as they can lose a different number of electrons
• For example. iron either:
  • Lose two electrons to form Fe²⁺ so has an oxidation number of +2
  • Loses three electrons to form Fe³⁺ so has an oxidation number of +3
• Compounds containing transition elements in different oxidation states will have different properties and colours