2. 1 Part 03 The Electron and Visible Light

3. 2 1.Quantum Mechanical Model of the Atom -electron occupies the area outside the nucleus -electron can be anywhere in the electron cloud -most likely location is its orbital -electron stays in its orbital unless it is energized

4. 3 2.Energizing Electrons -add heat ex. Bunsen burner, “Flame-Test” -add electricity ex. Discharge tube -add radiation reminder: radiation is any EMR. Ultra violet works well.

5. 4 3.Energized Electrons 1 e- will stay in ground state forever unless it is energized e-e- 2 Ground State e- can return to ground state state but only by giving out out the energy that went in Energy In Heat, Electricity, Radiation Energy Out We see this energy as colored light. QuantumLEapQuantumLEap Excited State This electron swallows a “gulp” or quantum of very specific energy to make the quantum leap.

6. 5 1 2 4 3 5 6 Balmer Series of the Emission Spectrum Visible through a Spectroscope For the simplest element, hydrogen, When an electron returns from EL 6 to EL 2, violet light is emitted. When an electron returns from EL 5 to EL 2, blue-violet light is emitted. When an electron returns from EL 4 to EL 2, blue-green light is emitted. When an electron returns from EL 3 to EL 2, red light is emitted. http://astro.u-strasbg.fr/~koppen/discharge/

7. 6 Emission of Radiation in the Form of Visible Light After Energy Absorption Incandescence Emission of light by a body solely as a result of its high temperature Luminescence Emission of light by a body not solely as a result of a rise in temperature Fluorescence Emission of light from a body while it is being exposed to electromagnetic radiation Phosphorescence Continued emission of light from a body after it has been exposed to electromagnetic radiation Chemiluminescence Emission of light from a cold body that is not being irradiated; luminescence that is the result of a chemical reaction Triboluminescence Emission of light caused by rubbing, mechanical action or fracture Bioluminescence Chemiluminescence occurring in a living organism

8. 7 The “Bright-Line” or “Emission” spectrum is emitted from the tube. These are different colors that are given off due to quantum leaps and then returning to lower levels. These very specific colors of light are all emitted all at once showing the blend of colored light. This colored light is then separated by a prism or diffraction grating. Every element has a different spectrum due to different numbers of electrons AND different energy level spacing.

9. 8 This spacing is different for each element. http://mhhe.com/physsci/chemistry/essentialchemistry/flash/linesp16.swf

10. 9 The absorption spectrum,“Dark Line” spectrum, shows the continuous spectrum except the energy absorbed by the gas. Assignment : Read pages 135-140; Section Review p 140