2003 Virginia SOLs
The cloud or quantum model of the atom is abstract and difficult to visualize. This model offers a three-dimensional representation for the student to ground understanding. Though the model possesses shortcomings, it offers the student insight into the density of the nucleus compared to the overall density of the atom. It further demonstrates the spacing to the electrons at relatively large distances from the nucleus. If the relative masses and sizes of the nuclear particles to electrons are large, the model emphasizes the important and natural size differential. It fails to show the quantum of orbital nature of the electron arrangement, however. Also, the nucleus is on the edge of the electron cloud unlike the expected central location. These deficiencies, however, can serve to bolster student understanding of the overall structure.
The models can be built by the teacher for demonstration and discussion. Conversely, students, individually or in groups, can build a model that reemphasizes the interpretation of periodic table data. With the models in hand, students can answer questions about them and can discover qualities of atomic structure rather than only receiving lecture based information on the topic.
Students must be reminded that when they are inflating the balloons, they must not inhale while their mouths are still on the balloon.
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1. Which atom did you model? Write its name and symbol in the space below.
2. How many protons, neutrons, and electrons are in your model?
Number of Protons: _____________________
Number of Neutrons: _____________________
Number of Electrons: _____________________
3. What object(s) represent the protons, neutrons, and electrons in your model?
4. Which part of your model has the greatest mass? ____________________________
(This part of the model with the greatest mass represents the nucleus of the atom. In a real atom, it is the heaviest part and has the greatest density too.)
5. Where are the electrons in your model? __________________________________
(In a real atom, the electrons are arranged at different levels from the nucleus, but are far from the nucleus. Most of an atom is empty space! In the model, the "empty space" is not really empty but occupied by air.)
Students with Special Needs
The activity requires fine motor coordination to build the models. If students are not easily able to complete the activity as written, the teacher can construct the models for student examination and discussion.
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