Flame Tests (AQA GCSE Chemistry)
Revision Note
Did this video help you?
Flame tests
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
Examiner Tips and Tricks
Make sure you are specific about the colour of the flame, for example, you must say calcium ions form an orange-red flame, not a red flame.
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?