DateExperiment 3: Atomic Spectroscopy
The purpose of the atomic spectroscopy lab experiment was to investigate the relationship between visible light, which is the visibly observable range of electromagnetic radiation and the change in energy levels of an element. The line spectrum that was seen in the spectroscope was the evidence of excited atoms emitting electrons and radiating a spectrum of light as it moved from a higher energy state back down to a lower energy level. Using a spectrometer with diffraction grating, a hydrogen lamp was observed and emission wavelengths compared with the known wavelength values. Flames from ignited sodium chloride were also observed and wavelengths calculated. To calculate the …show more content…
On the other end was a narrow, vertical entrance slit for the light to enter and hit the diffraction grating and next to the vertical entrance slit was a long, rectangular illuminating slit with a ruler for measuring the wavelengths of the visible spectrum produced by the element. The spectroscope was aimed at a mercury discharge lamp where the visible lines of the emission spectrum were used along with the known emission lines of mercury to create a calibration standard with which to calculate the wavelengths of the spectrum of hydrogen. The calibration curve was created in Excel by plotting the positions of the spectral lines of mercury and the known wavelengths in nanometers (nm).
The hydrogen gas discharge lamp was viewed from a distance of 10-20 centimeters (cm) where a narrow beam of light entered the spectroscope and hit the diffraction grating, breaking up the individual colors, allowing the unique spectrum of the element to be observed and measured. The spectroscope was also used to view the spectrum generated by ignited sodium chloride from a distance of 20 cm. Additional detailed procedures may be found in the course lab manual. …show more content…
If the entrance slit was too wide, the observed spectral lines would not be too wide and not isolated enough to accurately note the specific wavelength measurement. If the entrance slit was adjusted to be too narrow, not enough light would enter to hit the diffraction grating and no spectral lines would be visible. Another challenge with this experiment was having adequate lighting to see the ruler on the illuminating slit without having too much lighting which could influence the attempt to isolate the wavelength from hydrogen alone.
The calculations of the energy of the wavelengths confirmed that energy is inversely related to the wavelength, noting that the higher the wavelength, the lower the energy in Joules (J). The highest energy calculated was the blue line in hydrogen with the lowest wavelength and the lowest energy level was the red line which had the highest wavelength. The blue line would be from electrons that reached a higher energy level and then emitted the color line as the electrons transitioned