Discuss the Rutherford experiment and what Rutherford and his colleagues saw during the experiment.
Answering 30 written questions (may include small videos to watch, and drawings)Â
I. Use this information for the next four questions. A type of reusable hand warmer is filled with a solution (sodium acetate) that normally solidifies at approximately 50°C (120° F). This material has a tendency to super cool (remain liquid below its melting point) until it is provided with a trigger to start the crystallization process. In these hand warmers, flicking a small metal disk will cause the sodium acetate to begin to solidify.
Watch the video to see how it works:
1.What happens to the temperature of the hand warmer after the disk is flicked?
2. The hand warmers maintain a temperature of nearly 50°C for an extended period of time, sometimes several hours if they are kept in an insulated coat pocket. Using the molecular model of matter, explain where is the energy coming from and how the hand warmers can stay hot that long.
3. The instructions say that the hand warmers can be reused after placing them in boiling water for a few minutes. What does this accomplish?
4. Citrus farmers sometimes spray their orchards with water when the temperature drops a few degrees below freezing. Explain how ice forming around an orange could keep the orange from freezing.
 II. Use this information for the following five questions. This table lists the melting temperatures of the metallic elements of Group 1A.
Element in Group 1A
Melting Temperature
Lithium
180.54°C
Sodium
97.72°C
Potassium
63.38°C
Rubidium
39.31°C
Cesium
28.44°C
5. What trend in melting temperature do you observe as you go down the column? Which of the two properties (atomic volumes or ionization energies) shows the same trend as the melting points?
6. What would you predict about the forces that hold atoms of cesium together in the solid metal compared to the forces that hold atoms of lithium together in the solid metal?
7. Copy this table, paste it into the text area, and use it to create an energy well diagram for magnesium (Mg). Copy and paste these two arrows to indicate electrons: ↓ ↑
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Shell 2
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Be sure to properly label your diagram. Use the letter V to represent the valence electrons of Mg. For example: V↑
8. Based upon your knowledge of the periodic table, would Mg easily give up valence electrons or not? Explain your answer.
9. List two other elements that will behave in a similar manner to Mg.
III. To demonstrate the photoelectric effect, an electroscope is charged with electrons. Light from a flashlight is focused on the electroscope. An ultraviolet (UV) light is subsequently used in the same experiment. The intensity of both types of light can be increased or decreased. Based on this information, answer the next six questions.
10. Describe what is observed in these two cases (using the flashlight and using UV light) in terms of a possible characteristic of light.
11. What conclusion is drawn from this experiment and why?
12. What would happen to the charge on the electroscope if the intensity of the flashlight shining on the electroscope was increased?
13. What would happen to the charge on the electroscope if the intensity of the UV light shining on the electroscope was increased?
14. What other types of light could be expected to discharge the electroscope and why?
15. If the experiment was repeated again with the electroscope positively charged, what do you predict would happen and why?
IV. Ernest Rutherford performed experiments on atoms in the early years of the 20th century. Answer the following three questions about Rutherford and his work.
16. Describe the Rutherford experiment and what Rutherford and his colleagues saw during the experiment.
17. Name and describe the model of the atom that was shown to be inadequate by the Rutherford experiment. Why was this model inadequate?
18. Name and describe the model of the atom that was developed to account for the results of the Rutherford experiment. Discuss how the new model explained the new experimental results.
V. Reflection, refraction, interference, and diffraction are wave phenomena. Interference and diffraction are only exhibited by waves. Answer the next three questions about this.
19. What is meant by interference of waves? Describe and explain the example of interference produced when two closely spaced sources initiate water waves of the same frequency. Be sure to explain when constructive and destructive interference occur.
20. What is the difference between refraction and diffraction?
21. If you were to send a red laser beam into a glass of water, what would happen and why?
VI. The next three questions pertain to the following situation: A single electron is sent through a tiny slit. Later, it is detected by a screen that is placed on the opposite side of the slit. It is possible to change the width of the slit.
22. What is observed on the screen?
23. Is it possible to predict exactly where the electron will be seen when it arrives at the screen?
24. The slit is made narrower in an attempt to know exactly where the electron is when it passes through the slit. Will we now be able to predict where the electron will be seen? Explain your answer in terms of the Heisenberg Uncertainty Principle.
VII. For the following four questions, consider the quantum mechanical model of the atom.
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25. What is an orbital?
26. What is the connection between a standing wave and an orbital?
27. Why are only certain orbitals possible in an atom?
28. Describe the energy changes that occur when an electron associated with one orbital goes to a different, higher energy orbital. Be sure to account for all of the energy.
VIII. A light beam from a red laser is allowed to pass through two, close, narrow slits and then fall on a screen. No attempt is made to measure the light before it hits the screen and a great many photons are sent through at the same time. Based on this, answer the next two questions.
29. Describe what is observed in terms of a possible characteristic of light.
30. What conclusion is drawn from this experiment about the nature of light and why?
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