The Chemistry Book

Lesson: 50
Unit: 1
State Content Standard: Atomic and Molecular Structure

Lesson Title: Emission Spectra
Textbook page: Pages 326 - 327
Chemistry Passport: Page 64

Objectives
1. To measure the wavelengths of visible light emitted by an atomic element.
2. To identify elements.
3. To measure the energy released as a photon.

Lesson Content

• A Look at Emission Spectra*

> Emission Spectra results from an excited electron moving to a ground state.

> Another Definition: The process by which energy of a particle is converted to a lower energy level through the emission of a photon.

> Emission Spectra are usually independent of the excitation wavelength, because of rapid relaxation.

> Results are in different colors depending on the type and amount of light given (look at drawing).

> The spectral lines are unique to the atom.

> High Energy Photon = Short Wavelength >Low Energy Photon = Long Wavelength

For example: Red light has less energy than blue light. > Energy can be added to atoms many different ways. It can be in the form of light, an electric discharge or heat.

> Different elements emit different emission spectra when they are excited because each type of element has a unique energy shell or energy level system.

> Also look at Bohr model: http://www.thechembook.com/wiki/index.php/Bohr_Model

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