Question 6.F.1: (a) Based on your understanding of atoms and their spectra, ......
(a) Based on your understanding of atoms and their spectra, speculate on why streetlights that use sodium lamps seem yellow/orange in color. (b) What device or instrument could be used to make a measurement that would test your hypothesis from (a)?
Strategy This question involves conceptual problem solving. We can approach questions like this by asking what atomic or molecular level information must be inferred to answer it. Then we need to think about what sort of measurement or experiment could provide the atomic or molecular information needed to confirm or refute our idea.
(a) The key words in this question are “sodium lamp.” This description implies that there is something important about the lamp that is related to the element sodium. We saw in this chapter that atoms have distinctive spectra, so it is reasonable to surmise that in the case of sodium atoms enough colors are missing that the remaining light appears yellow/orange. (b) We could test this hypothesis by using a spectrometer or prism to view the light from the lamp. If our assertion is correct, the spectrum should show lines in the yellow-orange region but not in other parts of the visible spectrum.