Name: __________________________________________________________________________________ Date:__________ Block:______
Flame Test Lab
Purpose:
_____________________________________________________________________________________
Background: Electrons occupy only specific energy levels. When an atom absorbs sufficient energy, like when they are
heated, an electron can “jump” to a higher energy level. Higher energy levels, excited state, tend to be less stable, and will
eventually “fall” back to the lower energy level, the ground state. The absorbed energy is given off in the form of light.
White light is a continuous spectrum in which all wavelength of visible light are present. An excited atom,
however, produces one or more specific lines in the spectrum. Theses lines correspond to the specific changes in energy
levels of its electrons.
Flame tests are a quick method of producing the characteristic colors of metallic ions. Just as a fingerprint is
unique to each person, the color of light emitted by metals heated in a flame is unique to each metal. The loosely-held
electrons of a metal are easily excited in the flame of a lab burner. The release of energy as electrons return to a lower
energy level produces a colored flame.
Materials:
Barium
Calcium
Strontium
Copper
Potassium
Sodium
Copper
Beaker of water
Wooden flint
Bunsen Burner
Beaker of 0.1 M HCl
Unknown 1
Unknown 2
Unknown 3
Pre-Lab:
Pre-lab Questions
1. Describe what the ground state and excited state.
2. Arrange the colors of visible light spectrum in order from lowest energy to highest energy. (Blue, red, orange,
indigo, violet, yellow, & green)
3.
Relate wavelength and frequency to the amount of energy.
4. Write out the electron configurations for:
a. Barium
b. Copper
Precautions:
1
2
3
Procedure:
1. Put on goggles.
2. Pull hair and sleeves back
3. Put on apron
4. Report to your groups designated starting station
5. Fill a 100 mL beaker half full with water
6. Put the wood splint in the water for 1-2 minutes
7. Light the Bunsen burner.
8. Adjust the flame.- see Bunsen Burner Lab
9. Take note which sample you have at your station
10. Open the canister
11. Dip the wet wooden splint inside
12. Place the sample covered side of the wooden splint in the center of the flame.
13. Observe & record the distinct color that is emitted.
a. Do this immediately as the color may change the longer the splint is left in the flame.
14. Turn off the Bunsen burner.
15. Put the wooden splint in the beaker of water.
16. Change stations
17. Repeat steps 7-16 for each sample to be tested.
Data Table:
Metal
Color- be specific
Barium
Metal
Sodium
Copper
Calcium
Potassium
Strontium
Color/Observations- be specific
Color- be specific
Identity
Unknown 1
Unknown 2
Unknown 3
Conclusion:
1. Which elements are easiest to identify? Discuss what makes them easy?
2. Which elements are most difficult to identify? What makes them difficult?
3. Explain what happens to the electrons as they are being heated.
4. In this lab you observed that the colors of the flames in each sample are different. Why don’t all flames have the
same color? Explain.
5. Use last class computer activity, the demo, and this lab to explain: how do you think metals are used in
fireworks?
6. How might this method of identifying elements be important in real life? Explain when it would be handy to
identify unknown elements.
7. Answer:
a. I have a theory that states there’s a small amount of the element platinum in the sun. Using what you
know about light emission from atoms, explain how I might prove or disprove this theory.
b. Ultimately, what data must be known to confirm this hypothesis?