Lab 5 Electron Configuration CHEM101L ✓ Solved

Lab 5 Electron Configuration CHEM101L

Access Code (located on the lid of your lab kit):

Pre-Lab Questions

1. What is electron configuration?

2. How is the light emitted by an atom related to its electron configuration?

Data Table 1: Results of firework material ignition

Post-Lab Questions

1. Write out the electron configurations for each of the following elements. Potassium is already done as an example for you. HINT: The periodic table is very helpful and can be used as a guide.

2. What is the approximate wavelength of light emitted by each of the salts?

3. Why does a salt compound give off light or a colored flame when burned?

4. Did sodium chloride and potassium chloride give off similar colors? Why or why not?

Experiment 1: The Chemistry of Fireworks

Experiment Inventory Materials:

• 5 mL Calcium Chloride Solution (CaCl₂)
• 5 mL Lithium Chloride Solution (LiCl)
• 5 mL Potassium Chloride Solution (KCl)
• 5 mL Sodium Chloride Solution (NaCl)
• Matches
• Modeling Clay
• 3 Birthday Candles
• Labware
• 4 Inoculating Loops

Procedure

1. Place a round piece of clay on the straight end of each inoculating loop. This will act as a holder.
2. Place in order the LiCl, NaCl, KCl, and CaCl₂ solutions. Set one inoculating loop next to each sample.
3. Stabilize one birthday candle by placing the base of it in a piece of clay that is about 1 inch by 1 inch by 1 inch. The candle should stand freely and vertically.
4. Use the matches to light the stabilized birthday candle. Hold the inoculating loop for the LiCl at the very end of the non-looped end to avoid burns.
5. Heat the looped end in the candle flame until its loop is faintly orange and any coating is burned off.
6. Dip the loop into the LiCl solution.
7. Bring the looped end of the inoculating loop into the flame. Make observations about what is happening, especially any color changes.
8. Extinguish the candle, and record your observations in Table 1 on the Experiment 1 Data Sheet.
9. Repeat Steps 4–7 for each of the other three solutions. Use a different inoculating loop for each one.
10. When you’re done, take a photo of your experiment set up. Remember to include your name and lab access code handwritten in the background of the photo.

Lab Safety

Wear your safety glasses and choose an area that is well-ventilated (yet not windy), and have a fire extinguisher nearby. The candle should be on a flat surface. Matches, chemicals, and candle wax can cause a fire or burns to skin, clothing, or lab materials. Do not place any body part, loose clothing, or other flammable items in or near the flame. Never leave any burning fuel unattended!

Conclusion

The chemistry of fireworks illustrates the connection between electron configurations and the light emitted by different compounds. Through the ignition of the salts, we observe distinctive flame colors, which can be directly linked to the specific electron transitions occurring within the atoms of each element. Understanding these concepts allows for a deeper appreciation of both chemistry and the science behind fireworks.

References

• Atkins, P. W. (2010). Physical Chemistry. Oxford University Press.
• Bishop, S. (2012). Chemistry: A Molecular Approach. Pearson.
• Brown, T. L., LeMay, H. E., & Bursten, B. E. (2012). Chemistry: The Central Science. Pearson.
• Gello, S. (2021). Introduction to Electron Configuration. Journal of Chemical Education.
• Chemical Education Resource Center (CERC). (2020). Light Emission in Chemistry.
• Moore, J. W., & Stanitski, C. L. (2009). Chemistry: The Molecular Science. Brooks/Cole.
• Timberlake, K. C. (2016). Chemistry. Pearson.
• Rosenberg, D. E., & Dirks, R. E. (2014). Flame Test Colors: What We Learn from Firework Chemistry. Chemistry Education Research and Practice.
• Garcia, M. T. (2015). Safety Practices in Chemistry Labs. Journal of Chemical Safety.
• American Chemical Society. (2018). Guidelines for Lab Safety. ACS Publications.