Abstract
Chemistry
Published: Not Published
In this experiment, you will use a spectrophotometer to measure the distinct wavelengths of light emitted in the UV and visible range by electron relaxation in hydrogen, helium, and neon. Before starting the lab, make a table in your lab notebook for the elements that you will analyze, the color of the light that you observe from the lamps, and the recorded wavelengths.
Elements | Color | Distinct wavelengths, λ (nm) |
H | ||
He | ||
Ne |
Click Here to download Table 1
Rydberg constant (m-1) | 1.098 × 107 | |||
c (m/s) | 2.998 × 108 | |||
h (J·s) | 6.626 × 10-34 | |||
ni → nf | λcalculated (nm) | λmeasured (nm) | v (THz) | E (eV) |
7 → 2 | ||||
6 → 2 | ||||
5 → 2 | ||||
4 → 2 | ||||
3 → 2 |
Look at the calculated energies. You should see a trend of the energy gap increasing by less with each added energy level. This is reflected in the spacing of the peaks in the hydrogen emission spectrum. Helium and neon share this energy level spacing trend.
From the helium spectrum, adding even one more electron makes the spectral series harder to calculate and identify. This is even more apparent in neon, which has eight more electrons than helium.
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