1. Friday Oct 17 Objective: Observe the emission spectrum of different elements and compare it with white light. Checkpoint: What ion does aluminum form after it gains or loses electrons? What ion does nitrogen form after it gains or loses electrons? How many energy levels does cobalt have? How many energy levels does uranium have? HW: Emission spectrum lab (due Tuesday) Al N 3 + 3 -

3. Electromagnetic Spectrum

4. Wavelength of Light The shorter the wavelength ( ) of light the higher the frequency and higher the energy of the wave. Higher energy Lower energy

5. Infrared Waves Thermal Vision

6. Photoelectric Effect When atoms absorb energy from an external source, they emit light. Absorbing energy causes electrons to jump to a higher energy level.

7. When the electron goes back down to its original energy level, it emits a photon of the same amount of energy it originally absorbed. Photoelectric Effect

8. How many different photons can an atom with 3 energy levels emit? Photoelectric Effect

9. How many different photons can an atom with 3 energy levels emit? Photoelectric Effect

11. Emission Spectroscopy Lab Pre-lab questions: 1.According to the modern theory of the atom, where may an atom’s electrons be found? 2.How do electrons become “excited”? 3.What form of energy emission accompanies the return of excited electrons to the ground state? 4.Assume that an atom has a total of four possible energy levels and that an electron can jump up or down between any of these energy levels. Draw a model of these energy levels, and use it to predict the maximum number of spectral lines in the emission spectrum.

12. Emission Spectroscopy Lab Data : Sunlight/white light Fluorescent light

13. Emission Spectroscopy Lab Post-lab questions: 1.Compare the spectra produced by sunlight (white light) and fluorescent sources. What are the similarities? What are the differences? 2.Some elements have the same color, but brighter spectral lines than others. How can the difference in the brightness be explained? 3.Prior to its discovery on Earth, the existence of helium was first confirmed in the sun. Explain how this can be possible.

14. Friday: Values Talk Compassion Integrity Responsibility Courage Respect Curiosity Name: _______________ Class: _______________ 1)Which of the 6 characteristics are you the strongest in? Explain why. 2)Which of the 6 characteristics do you feel you could most improve in? Explain why.