Excited Elements by CedricFebis

VIEWS: 13 PAGES: 12

									Excited Elements
Introduction

•As electrons absorb energy they become excited
 and move to higher energy levels.
•This energy is released in set amounts of energy
 (quanta) as the electrons fall back into lower
 energy levels.
•This energy is released in many regions of the
 electromagnetic spectrum, including the visible
 region that you can see.
•Quanta of light energy is called photons.
   In this lab, gases under low pressure receive
    electrical energy to excite the electrons.
   The electrons give off light in unique
    wavelengths and frequencies.
   The emitted light is passed through a
    spectroscope, which breaks light into its bright
    line emission spectrum.
   Each element produces a unique bright-line
    spectrum because each has a different number
    of electrons.
   The lines produced depends on the electron
    transition in that particular atom.
   When a solid is heated until it glows, it
    produces a continuous spectrum instead of a
    line spectrum.
   Spectroscopy is a valuable tool identify
    elements in samples.
   The composition of stars and other objects in
    outer space is determined using this technique.
   Helium was discovered as one of the elements
    in the sun before finding it here on Earth.
Purpose:


• To observe the characteristic bright line
  emission spectra produced by different
  elements.
• Identify unknown samples by comparing
  unknown bright line spectrums to those that are
  known.
Equipment/Materials:

•High voltage power supplies
•Diffraction grating glasses
•Spectroscopes
•Colored pencils
•40 watt incandescent bulb/socket
•40 watt fluorescent bulb/socket
•Thermal Mitt
•Spectral Tubes : Hydrogen, Helium, Neon,
 Mercury, Nitrogen, any other samples, and one
 unknown gas.
Use white box for reflection; easier
to read numbers on spectroscope!
Safety:

•DO NOT TOUCH the spectrum-tube power
 supply or spectrum tubes. Several thousand
 volts exist at the power supply and spectrum
 tubes are delicate.
Procedure

   Obtain a spectroscope and look through it at
    an incandescent light bulb.
   The spectrum should appear when the slit in
    the spectroscope is pointed towards the bulb,
    just off center.
   Practice moving the spectroscope until you see
    a bright, clear image.
   Observe the color given off by the gas in the
    spectrum tube.
   Next, put on the diffraction grating glasses and
    observe the bright line spectra tube.
   Next, use a spectroscope and adjust it until the
    brightest image is oriented on your scale.
   Record the five brightest lines using the
    corresponding colored pencil and mark the line
    at the wavelength where it appears in the
    spectroscope.
   Repeat this for all known samples and the
    unknown sample.
   Observe and record the bright line spectrum for
    the fluoresent light.
   Observe and record the bright line spectrum for
    the incandecent light.
This is how AUSIM packs
    the spectra tubes!

								
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