1. Warm Up 10/21 Where can electrons be found in an atom? What is their electric charge?

2. Lesson: Electcromagnetic Spectrum (EMS)

3. Parts of a wave Wavelength – Distance between two corresponding points on successive waves. Amplitude – measure of a wave’s “strength” (height of crest or trough).

4. The Wave-like Electron Louis deBroglie The electron propagates through space as an energy wave. To understand the atom, one must understand the behavior of electromagnetic waves.

5. Electromagnetic Wave – An electric wave and magnetic wave moving at right angles to each other.

6. Electromagnetic Spectrum – Arrangement of all forms of electromagnetic radiation in order of frequency and wavelength.

7. Frequency (ν): number of wavelengths that pass a certain point in a given amount of time. - units are Hertz (Hz) If these 2 waves are traveling at equal speeds, which wave will have more wavelengths cross the finish line in one minute? FINISH low frequency high frequency = short wavelength = long wavelength

8. If these 2 waves are traveling at equal speeds, which wave will have more wavelengths cross the finish line in one minute? FINISH low frequency high frequency = short wavelength = long wavelength

9. Left Side Practice 1) Pick a type of wave on the EMS (not visible light). 2) Draw a pic of that wave and label the crest, trough, wavelength and amplitude. 3) Write and answer these questions: Does it have a greater wavelength than visible light? Does it have a higher frequency than visible light? Does it have more or less energy than visible light?

10. 3) Write and answer these questions: Does it have a greater wavelength than visible light? Does it have a higher frequency than visible light? Does it have more or less energy than visible light?

11. Warm Up 10/22 Which type of EM wave do you think travels the fastest?

12. Wavelength (λ) and frequency (f) are inversely related. All waves on the EMS travel at the speed of light (c). c = λ (f) c = speed of light = 3.00 x 10 8 m/s. o to solve for λ … c λ = f o to solve for f … c f = λ

13. Practice Calculate the f of a wave that has a wavelength of 5.00 x 10 -6 m. c f = λ f = = f Hz Does this radiation have a shorter or longer λ than red light?

15. What is the wavelength of radiation with a frequency of 1.50 x 10 13 Hz? c λ = f λ = λ = Practice

16. Calculate the wavelength of yellow light emitted by a sodium lamp, if the frequency of the radiation is 5.10 x 10 14 Hz. On Your Own Practice * Hint: Be sure you set up the right equation. Ask yourself: which variable am I solving for?