Nader Makarious
Flame Test
Background:
When atoms or ions are heated, they gain kinetic energy; some electrons may absorb
enough energy (photon) to “jump” to higher energy levels (excited state). Excited electrons don’t
last long in the higher energy levels (unstable state); the electrons will “fall” back to their ground
state and release the extra energy (equal to the difference between ground state and excited state).
When the energy released in the visible light spectrum, a certain color can be seen. The color of
the light depends on the energy change that took place (wavelength and frequency). Many
metallic ions exhibit characteristic colors when heated; therefore, the color of the light can be
used to identify certain elements, that’s why these colors are called fingerprint of elements.
Materials: Chemicals:
Nichrome wire loop Nitrate solutions of the following ions:
Bunsen burner Na+, K+, Li+, Ca2+, Sr2+, Ba2+, Cu2+
50 mL beaker concentrated hydrochloric acid HCl
10 mL graduated cylinder
Safety:
Safety goggles, gloves, and aprons have to be worn all the time during the lab.
Procedure:
1. Read the entire laboratory, and then develop a data table to collect all data and observations
required for this experiment.
2. Put about 10 mL of concentrated hydrochloric acid into a clean, dry 50 mL beaker.
3. Clean the wire loop. To do this, dip the loop in the acid and then heat the loop in the outer
edge of the burner flame. Continue to clean the loop until no color is observed in the flame.
4. Dip the clean wire into one of the solutions. Place the loop in the outer edge of the burner
flame and move the loop up and down. Note the color in the flame. Watch closely, looking
for the first hint of color observed. Record your observations in a data table.
5. Clean the wire loop and repeat step 3 with a different solution. Test each solution, cleaning
the loop thoroughly between each test. Record all observations in a data table.
6. Obtain samples of unknown solutions (at least five different solutions). Note the
identification of the unknown and the color of the flame in your data table. Identify the
metallic ion present by the color of the flame.
