Identifying Metal Cations

  • Metal ions produce a colour if heated strongly in a flame.
  • Ions from different metals produce different colours.
  • The flame test is thus used to identify metal ions by the colour of the flame they produce.
  • Dip the loop of an unreactive metal wire such as nichrome or platinum in dilute acid and then hold it in the blue flame of a Bunser Burner until there is no colour change.
  • This cleans the wire loop and avoids contamination. This is an important step as the test will only work if there is just one type of ion present.
  • Two or more ions means the colours will mix, making identification erroneous.
  • Dip the loop into the solid sample and place it in the edge of the blue Bunsen flame.

Identifying Metal Cations, IGCSE & GCSE Chemistry revision notes

Diagram showing the technique for carrying out a flame test

  • The colour of the flame is observed and used to identify the metal ion present.

Colours of metal cations, IGCSE & GCSE Chemistry revision notes

Diagram showing the colours formed in the flame test for metal ions

Results

Identifying Metal Cations Table, IGCSE & GCSE Chemistry revision notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.