Nobel-ity, Part 1 How do chemists design stable compounds? I can show how noble gases remain stable.

Nobel-ity How do you design a molecule? Why are some molecules stable, and not others? How would you make a molecule that was useful? Nobel-ity

Stable molecules What do you think this molecule does? Why is it stable? Stable molecules

Question 1, p. 176 Redraw the hydrogen spectra How many lines? What color is each? Question 1, p. 176

A. How do you know that the Rutherford model of atom structure did not explain line spectra? Hint: did the Rutherford model have different energy levels for electrons? Question 2, p. 177

B. How do you know that each line is associated with a different amount of energy? Does each color have a different energy? Think about wavelengths. http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::800::600::/sites/dl/free/0072482621/59229/Bohr_Nav.swf::The%20Bohr%20Atom http://player.discoveryeducation.com/index.cfm?guidAssetId=244FD84B-CF9C-45F1-9113-23CC31234874 Question 2, p. 177

C. Why do you think that rapidly moving electrons, not rapidly moving protons, are responsible for spectral lines? Which one is easier to move? Which one is “fatter”? Question 2, p. 177

D. How were differences in the amount of dark spaces between lines important? What does it have to do with energy? Question 2, p. 177

Read the reading! Words: Quantum (Quanta) Orbit Question 4, p. 177

Niels Bohr (Born in Denmark 1885-1962) Student of Rutherford

Niels Bohr’s Model (1913) Electrons orbit the nucleus in circular paths of fixed energy (energy levels).

Max Plank E=hn E=energy n=frequency h=Plank’s constant 6.7x10-34Js

Energy of Emitted Photon Energy of the emitted photon = Difference in energy between two states

Energy emitted by the electron as it leaps from the higher to the lower energy level is proportional to the frequency of the light wave. Frequency define the color of visible light.

Bohr Atom http://higheredbcs.wiley.com/legacy/college/halliday/0471320005/simulations6e/index.htm?newwindow=true

Niels Bohr’s Atom Cont’d Electrons can jump from energy level to energy level. Electrons absorb or emit light energy when they jump from one energy level to another.

Quantum A quantum of energy is the amount of energy required to move an electron from one energy level to another.

The energy levels are like the rungs of a ladder but are not equally spaced.

Photons Photons are bundles of light energy that is emitted by electrons as they go from higher energy levels to lower levels.

Excited State and Ground State Ground state: the lowest possible energy level an electron be at. Excited state: an energy level higher than the ground state.

Emission Spectrum Light emitted produces a unique emission spectrum.

Hydrogen Emission Spectrum Violet Blue Red Balmer Series

Bohr Model for Hydrogen

The Bohr model explained the emission spectrum of the hydrogen atom but did not always explain those of other elements.

Use the stuff I taught you and the stuff in the book to help your responses A: Why did Rutherford’s model of atoms not explain spectra? Make a labeled sketch with highlight comments and a caption B. Complete the table (figure 4.11) Use statements from the reading Do AT LEAST all that, plus more if needed Question 5

Examine chemical symbols in the book Examine chemical symbols in the book. They explain 2 important aspects of the Bohr model A. Which expression shows an ABSORBTION of energy? B. Which shows an EMISSION of energy? C. Which particle transports energy away from the excited state of Sr when it falls to the ground state? D. Based on flame Question 6

D. Based on flame tests, what is a reasonable hypothesis about the color of an emitted photon from strontium? E. Did the heat of the flame ionize the Sr+2 ion? How do you know? Question 6