1. Unit 2: Atoms and Bonding 2.61 Light Textbook ch 6.1

2. Big Idea 1: The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions. Students will be able to demonstrate understanding by laboratory investigation, analysis of data and creation of models. SWBAT: Calculate the wavelength of electromagnetic radiation given its frequency or its frequency given its wavelengthCalculate the wavelength of electromagnetic radiation given its frequency or its frequency given its wavelength Order the common kinds of radiation in the electromagnetic spectrum according to their wavelength or energyOrder the common kinds of radiation in the electromagnetic spectrum according to their wavelength or energy Learning Objectives :

3. The ELECTRON: Wave – Particle Duality Graphic: www.lab-initio.com

4. The Dilemma of the Atom Electrons outside the nucleus are attracted to the protons in the nucleusElectrons outside the nucleus are attracted to the protons in the nucleus Charged particles moving in curved paths lose energyCharged particles moving in curved paths lose energy What keeps the atom from collapsing?What keeps the atom from collapsing? Electrons outside the nucleus are attracted to the protons in the nucleusElectrons outside the nucleus are attracted to the protons in the nucleus Charged particles moving in curved paths lose energyCharged particles moving in curved paths lose energy What keeps the atom from collapsing?What keeps the atom from collapsing?

5. Wave-Particle Duality JJ Thomson won the Nobel prize for describing the electron as a particle. His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron. The electron is a particle! The electron is an energy wave!

6. 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.

7. Waves Wavelength= measured crest to crest Frequency = # of complete wavelengths or cycles That pass a certain point per second

9. Parts of A Wave wavelength distance between two consecutive peaks or troughs in a wave symbol: lambda, units: meters (m) frequency the number of waves passing a point in a given amount of time symbol: nu, units: cycles/sec or 1/sec or sec -1 or Hertz (Hz) peak/crest trough node

10. c = c = c = speed of light, a constant (3.00 x 10 8 m/s) = frequency, in units of hertz (hz or sec -1 ) = wavelength, in meters Electromagnetic radiation propagates through space as a wave moving at the speed of light.

11. Conversions needed to do these problems 1nm = 1 x 10 -9 m 1hz = 1/s = 1 s -1 Hz = hertz, a unit for frequency s = seconds s -1 = per second

12. The Electromagnetic Spectrum Gamma rays wavelength similar to diameter of atomic nuclei Gamma rays Radio waves longer than a football field Increasing

13. 1. 1.Which wave has a higher frequency? 2. 2.Which wave has a longer wavelength? 3. 3.If one represents blue light and one represents red light- which is which?

14. Try this one… The yellow light given off by a sodium vapor light has a wavelength of 589nm. What is the frequency of this radiation?

15. References Our textbook: Brown, Lemay et all. AP edition chemistry, 13 th edition, 2015 www.sciencegeek.net/Chemistry and Mr. Perekupa’s PPT Cinnaminson.com from Cinnaminson High school. I modified the original PPTs to fit our needs in AP Chemistry.