Electron Arrangement and EMR

1
2.05

• Electron Arrangement and EMR Virtual Lab Line
  Spectra

2
Part I Flame Tests

• How do atoms produce light?
• When energy is added to an atom, the electrons
  will absorb the energy and move to higher energy
  levels.
• The electrons are now in the excited state
• Unstable, temporary situation
• Consequently electrons will fall back down to a
  lower energy level, dispersing the added energy
  in the form of Electromagnetic Radiation (light)
• The difference of energy will determine which
  color of light is emitted

3

• We can use the color of light to determine the
  locations of the electron orbitals.
• The differences in orbital location and potential
  energy are unique to every element.
• We can use the color produced to identify the
  element.

4
(No Transcript)
5
Flame Test Results
6
Identification of the Unknown Solutions
Element Flame Color
Barium
Calcium
Potassium
Rubidium
Sodium
Lithium
Unknown 1
Unknown 2
Lab Report Fill in data table with the flame
colors (5 points)   Identify each unknown from
part 1 of the lab, and briefly explain why you
identified each unknown as you did. (2 points)
7
Part II - Spectroscopy

• Spectroscopy is the analysis of line spectra and
  of the way light interacts with matter
• Light passes through a narrow slit to produce a
  beam of light. It is then separated using a
  prism. Different colors of visible light appear
  as different lines according to their
  wavelengths.
• Different elements produce different line
  spectra. There is unique spacing between the
  energy levels

8
How spectroscopy works
9
Hydrogen Line Spectra
Lab report Record the color and wavelength (nm)
for each line in your data table. (5 points for
entire data table)
10
Helium Line Spectra
Lab report Record the color and wavelength (nm)
for each line in your data table.
11
Sodium Line Spectra
Lab report Record the color and wavelength (nm)
for each line in your data table.
12
Neon Line Spectra
Lab report Record the color and wavelength (nm)
for each line in your data table.
13
Mercury Line Spectra
Lab report Record the color and wavelength (nm)
for each line in your data table.
14
Compare Spectrums
Lab Report Describe the line spectrum of the
star. Give the color and wavelength value of the
five brightest lines in the spectrum. (3 points)
15
Conclusion

1. Explain, in your own words, why different
   elements produce different colors of light when
   heated. (5 points)
2. Why do you think that the elements had to be
   heated before they emit the colored light? (2
   points)
3. What element do you think is the most abundant in
   the star that you observed in part 2? Explain
   your answer. (3 points)