Web Drop in #2

Created by Erik Heinemann for SLM 521

Click on the website for the line spectra for helium and nitrogen or type the following URL:

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/atspect.html#c1

This site provides line spectra analysis for the elements helium and nitrogen.

Your task is to investigate this website and some of the links associated with the site to complete the following outcomes:

1) Identify different line spectra for different elements

2) Define diffraction grating

3) Identify the source of line spectra

Words of caution: This website contains some links and mathematical functions that go beyond the scope of the high school chemistry class. Do not get lost in the mathematics, focus your attention on the concepts and the specific information requested here.

Activity: On notebook paper, answer the following questions.

1) Using general descriptions; compare the spectrum for helium to that of nitrogen.

2) What wavelengths (colors) are present in the helium spectrum?

Click on the link for argon.

3) Using a general description for each compare the line spectrum of argon to that of iodine?

4) Compare and contrast these two to helium and nitrogen.

Click on the link for neon.

5) Record the wavelengths (l) for neon and mercury.

6) Neon has several wavelengths that can be seen in the spectra, but the neon lights all look red. Looking at the wavelengths, offer an explanation as to why the lights in the signs look red.

From the Mercury lamp spectrum find and click on the link for diffraction grating.

7) Define diffraction grating.

8) What is the normal diffraction grating for CDs (or DVDs)?

Go back to Neon. From the Neon page click on the link for hydrogen.

9) Examine each of the diagrams carefully (ignoring some of the mathematics). Explain how the line spectra are created in terms of electrons and the Bohr model of the atom.

10) From what energy level to what energy level to moving electrons produce a violet color wavelength? A green or blue color wavelength? Red?

11) Although some wavelengths overlap and are common for different elements, do any of the spectrums examined match any of the other spectrums exactly? What does this tell you about each element examined and each element on the Periodic Table?

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