chemical test 1問。

As a matter of fact, both sodium chloride and sodium can also burn to form a golden yellow Bunsen flame.

The reason why both can burn to form a coloured flame is that as the election of sodium excites to the excited state when giving energy (by burning), it falls back to the ground state (which is more stable) and emit a photon (a light ray or energy carrier) with a certain frequency depending on the energy difference.

For sodium, the energy difference can produce a photon which is golden yellow in colour, that's why the flame colour is yellow.

Both the election of sodium ion or sodium can be excited, therefore they can also produce golden yellow flame.

The reason for potassium is just the same.

2007-05-28 15:05:14 補充：
Points to remember:1. Don't say " Heat/Warm the sodium chloride in a Bunsen flame ".Instead of it, you should say "Burn sodium chloride in a Bunsen flame."2. Remember to use a clean Pt wire to do the flame test, or a Pt wire that cannot produce any other flame colour.