Name:
Lab Partner:
Date:
Flame Tests
OBJECTIVES


Observe the characteristic colors produced by certain metallic ions when vaporized in a
flame.
Identify an unknown metallic ion by means of its flame test.
INTRODUCTION
The normal electron configuration of atoms or ions of an element is known as the “ground
state”. In this most stable energy state, all electrons are in the lowest available energy levels.
When atoms or ions in the ground state are heated to high temperatures, some electrons may
absorb enough energy to allow them to “jump” to higher energy levels. The element is then
said be in the “excited state”. This excited state is unstable, and electrons “fall” back to their
normal positions of lower energy. As the electrons return to their normal levels, the energy
that was absorbed is emitted in the form of electromagnetic energy. Some of this energy is in
the form of visible light. The color of this light can be used as a means of identifying the
elements involved. Such crude analyses are known as flame tests.
Higher Energy Level
Electromagnetic
Radiation
HEAT
“Visible Light”
Lower Energy Level
Electron in
“Ground State”
Electron in
“Excited State”
Electron in
“Ground State”
Only metals, with their loosely held electrons, are excited in the flame of a laboratory burner.
Thus, flame tests are useful in the identification of metallic ions. Many metallic ions exhibit
characteristics colors of several different metallic ions will be observed, and an unidentified ion
will be identified by means of its flame test.
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MATERIALS
Safety Goggles
Bunsen Burner
Nitrate Solutions
PROCEDURE
1.
2.
3.
4.
5.
6.
7.
8.
Put on your safety goggles.
Obtain the control, water.
Remove the wooden splint and then heat the splint in the
outer flame by moving the splint up and down.
Obtain a solution of a metallic ion.
Remove the wooden splint and then heat the splint in the
outer edge of the flame by moving the splint up and
down. Try not to burn the wooden splint or your data will
be compromised.
Note the color of the flame and record in the data table.
Replace the wooden splint to the original container.
Test each solution in the same manner.
DATA TABLE
Metallic Ion
Color
Control
Na+, Sodium
K+, Potassium
Li+, Lithium
Ca2+, Calcium
Sr2+, Strontium
Ba2+, Barium
Cu2+, Copper
Unknown
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ANALYSIS and CONCLUSIONS
1. Rank the metallic ions from the smallest wavelength to the longest wave length. Write the color
of the flame beneath each ion. Do not include the control or the unknown.
2. Rank the metallic ions from the lowest energy to the highest energy. Write the color of the
flame beneath each ion. Do not include the control or the unknown.
3. What metallic ion(s) was in the unknown? Explain.
4. How does an electron reach the excited state? Explain.
5. What occurs as an electron returns to the ground state from the excited state? Explain
6. Copper has two isotopes, Copper-63 and Copper-65. Copper-63 has a mass of 62.929 and
Copper-65 has a mass of 64.927. The average atomic mass of copper is 63.546 amu. What is the
abundance of each isotope? Show work.
7. What are similarities and differences between 63Cu1+ and 65Cu2+?
8. Which of the nitrates that you tested would give off a photon with a frequency of 5.50 x 10 14
Hz?
9. Which of the nitrates that you tested would give off a photon with an energy of 3.00 x 10 -19J?
Explain your reasoning.
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