Lesson 17

Flame Test

In class we did a flame test where we held a metal rod dipped in different solution over a flame to observe what colors appeared.

• A flame test is a test used in laboratory to look for the presence of certain metal atoms
• The metal element in each chemical formula appears to be responsible for the flame's colors
• Only certain elements produce colorful flames

The colors in the flames are caused by excited electrons

• Electrons move away from the nucleus
• When they move back they release light energy

        Red                     Yellow-orange            Blue-green                    Pink-lilac
   Lithium, Li               Sodium, Na            Copper, Cu                    Potassium, K
Lithium chloride        Sodium chloride          Copper chloride           Potassium chloride
        LiCl                             NaCl                           CuCl2                              KCl

 Practice Problems

1) How did the flame test provide evidence that specific atoms are present in compounds? The colored flames each had recurring elements.
6) What evidence do you have from flame tests that copper is responsible for producing a flame with a blue-green color? Each blue-green flame had copper in its compound.
10) If two chemical samples both produce an orange flame upon testing, which statement is true? C- the samples both contain calcium atoms

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