Flame Tests (AQA GCSE Chemistry)

• The flame test is used to identify the positive metal ion (cations) by the colour of the flame they produce
  • Ions from different metals produce different colours
• To carry out a flame test:
  • Dip the loop of an unreactive metal wire such as nichrome or platinum in dilute acid
  • Hold it in the blue flame of a Bunsen burner until there is no colour change
  • Dip the loop into the solid sample / solution and place it in the edge of the blue Bunsen flame
• It is important to place the wire into acid first to prevent contamination
  • Not doing this might result in two or more ions being present on the wire meaning the colours will mix
  • One colour could mask another colour and you will not be able to identify the ion

Flame tests

The blue flame must be used to carry out a flame test 

• The flame test colours can be seen below:

Metal ion	Colour of flame
Li+	crimson
Na+	yellow
K+	lilac
Ca2+	orange-red
Cu2+	green

Flame test colours

Metals form distinctive coloured flames