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How do you carry out a flame test
take a platinum/nichrome wire
Dip into concentrated hydrochloric acid and then heat in bunsen flame until no colour is seen
Dip wire into fresh concentrated hydrochloric acid then into metal salt
Heat wire and sample in flame
Why do you use a nichrome/platinum wire?
They’re unreactive with the air in the flame and do not have their own flame colour
Why is the wire dipped into hydrochloric acid and then heated (the first time)
To clean the wire of any other previous samples
Why is the wire dipped in concentrated HCl then in the sample
It reacts with the salts to form chlorides which are more volatile as they have lower boiling points as they need to be in the gaseous state for the tests to work.
Li+
Red/crimson
Na+
Yellow
K+
Lilac
Rb+
Red
Cs+
Blue/violet
Be2+
Colourless
Mg2+
Colourless
Ca2+
Brick red
Sr2+
Red
Ba2+
Apple green
How do flame tests work
electrons absorb the heat energy from the flame and move to higher energy levels
Electrons drop back down to lower energy levels
Light in visible region is released
Different energy gaps between levels cause different colours
