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AES Question sheet

Analysis and Detection
Atomic Emission Spectroscopy
Atomic Emission Spectrum of Elemental Sodium
You are going to view the atomic emission spectrum of sodium. Sodium is the element used in
street lights, giving them their distinct orange colour.
Firstly, look at the natural light coming from the window using the spectroscope (do
not look directly towards the sun). This is called white light. Notice what the
spectrum looks like.
Now look at the light coming from the sodium lamp using the spectroscope.
a). How does the spectrum for sodium differ from the spectrum for white light?
b). Which coloured lines are present in the spectrum of sodium? Which lines are the brightest?
How does this compare to the colour of the sodium lamp?
Use the spectra of the following elements to answer questions c) and d).
c). Astronomers use atomic emission spectroscopy to work out what elements are present in a
distant star. The spectrum below is for Alpha Centauri, the closest star to our Sun. What elements
are present in Alpha Centauri?
d). An atomic emission spectrum was taken, which is shown below, of a sample of steel during the
quality control process. The spectrum shows iron, but what other element has been found in the
© S. Coates, Bristol ChemLabS, 2008