Electron Configuration Lesson  

Content Area: Chemistry (10-12th grade)
Topic: Electron Configurations
Sub-Topic: Emission Spectra

Computer requirements: Internet access, ShockWave Plug-In
Prior content covered: Basic structure of the atom
Estimated time for computer portion of lesson: 15-20 min

Essential Questions or Ideas to Address:

  • How is the emission spectra related to electron configurations?
  • What does it mean to say that the electron energies are quantized?

The lesson: (90-min block)
Students observe the emission spectra of several gases in a lab setting using gas tubes and a diffraction grating slide. Students have recorded the observed spectra for hydrogen, helium and one or two other gases. The students then go to the computer lab and working in groups of two they access the Visual Quantum Mechanics web-site for emission spectra. They create energy level diagrams that match those of different gas tubes. On the recorded diagrams, students color the arrows with a color approximating the color produced by on the spectrum by that electron.

After they complete several diagrams, they return to the regular classroom for a discussion of how the spectra provide evidence for electrons being in orbitals.

Common misconception addressed: Students often believe that larger energy changes are associated with red and smaller energy changes are associated with blue wavelengths.

Evaluation of lesson effectiveness: While students initially have some difficulty with the website, after they learn the steps to create a diagram, they proceed with facility. Since this lesson has been in use, very few students have trouble remembering that high energy emission is purple and low energy is red.

Alternate presentation: This visualization could easily be part of a lecture discussion.

Extensions: Students could check out the absorption and emission spectra applet at

Note: Be sure to check out the other animations available at the main page for this web site
( http://phys.educ.ksu.edu/vqm/index.html ).


MSDE (from the website as of 9/05) :

Chemistry/Core Learning Goals
Science Indicator 4.2.1

The student will illustrate the structure of the atom and describe the characteristics of the particles found there. AT LEAST: protons, neutrons, & electrons, nucleus.

Indicator 4.2.2

The student will demonstrate that the arrangement and number of electrons determine the properties of an element and that these properties repeat in a periodic manner illustrated by their arrangement in the periodic table. AT LEAST: atomic number, mass number, valence electrons, chemical properties/families

Goal 5 Concepts Of Chemistry
The student will demonstrate the ability to use scientific skills and processes (Core Learning Goal 1) to explain composition and interactions of matter in the world in which we live.

Expectation 4.2
The student will explain that all matter has structure and the structure serves as the basis for the properties of and the changes in matter.

National Science Standards (9-12):

Physical Science:

  • Structure of Atoms:

    Matter is made of minute particles called atoms, and atoms are composed of even smaller components. These components have measurable properties, such as mass and electrical charge. Each atom has a positively charged nucleus surrounded by negatively charged electrons. The electric force between the nucleus and electrons holds the atom together.

  • Interactions of energy and matter:

    Waves, including sound and seismic waves, waves on water, and light waves, have energy and can transfer energy when they interact with matter.

AAAS Benchmarks (9-12):

The Physical Setting: Energy Transformations:

  • Different energy levels are associated with different configurations of atoms and molecules. Some changes of configuration require an input of energy whereas others release energy.
  • When energy of an isolated atom or molecule changes, it does so in a definite jump from one value to another, with no possible values in between. The change in energy occurs when radiation is absorbed or emitted, so the radiation also has distinct energy values. As a result, the light emitted or absorbed by separate atoms or molecules (as in a gas) can be used to identify what the substance is.

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