1. The Atom Electrons outside the nucleus are attracted to the protons in the nucleus (positive and negative charge attract!) When charged particles move in curved paths, they lose energy So, what keeps an atom from collapsing?

2. 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!

3. Louis deBroglie The electron moves through space as an energy wave. In order to understand an atom, we need to understand the behavior or electromagnetic waves

4. Electromagnetic Spectrum Video Electromagnetic Spectrum

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

6. The energy ( E ) of electromagnetic radiation is directly proportional to the frequency ( ) of the radiation. E = h E = h E = Energy, in units of Joules (kg·m 2 /s 2 ) h = Planck’s constant (6.6262 x 10 -34 J·s) = frequency, in units of hertz (hz, sec -1 ) = frequency, in units of hertz (hz, sec -1 )

7. Long Wavelength = Low Frequency = Low Energy Short Wavelength = High Frequency = High Energy

8. Electromagnetic Spectrum

9. Electron Transitions Electrons transitions involve jumps with definite amounts of energy This produces bands of light with definite wavelengths.

10. Flame Tests strontiumsodiumlithiumpotassiumcopper Many elements give off characteristic light which can be used to help identify them.

11. Questions 1.What are two states an electron in an atom might have? 2.Which of the two is the most stable state? 3.What happens when electrons fall back from one energy level to another? 4.Draw the Lewis Dot Diagram for calcium and lithium atoms. 5.Write the Noble Gas Configuration for antimony.

12. Electromagnetic Radiation Problems 1.What is the energy of a frequency of 5.6 x 10 15 hz? 2.What is the wavelength of the above frequency? 3.A red light has a wavelength of 600 nm, what is its frequency? Equations: E = h v c = c = speed of light = 3.00 x 10 8 m/s h = 6.6262 x 10 -34 J·s)