Spectra Analysis Lab   Emission spectra of elements are the result of electron transitions within atoms and provide information about the arrangement of electrons in the atoms. Observe and compare a spectrum from white light with the emission spectra of several elements. Procedures: Obtain a diffraction grating from the teacher. Hold it only by the edges and avoid touching the transparent material. Observe the emitted light from an incandescent bulb through the grating as you hold it close to your eye. Record your observations by marking on the data table the color and width of the lines you see. Next observe the light produced by the spectrum tube containing hydrogen gas and record your observations on the data table. Cation: The spectrum tube operates at a high voltage. Under no circumstances should you touch the spectrum tube or any part of the transformer. 4. Repeat procedure 3 with the other spectrum tubes as your teacher designates.

R O Y G B V White Light Hydrogen Iodine Nitrogen Argon Xenon Helium   R O Y G B V White Light Hydrogen Iodine Nitrogen Argon Xenon Helium Neon

Analysis: How do you explain why only certain colors appear in emission spectra of the elements? If each hydrogen atom contains only one electron, how are several emission spectra lines possible? How do you interpret the fact that other elements emit many more spectral lines than hydrogen atoms?