
Students will
Computer Demonstration: Atomic Modeling
To give students an idea of the shapes and scales of atoms, link to http://www.colorado.edu/physics/2000/applets/a2.html for a fully interactive periodic table. This table allows teachers and students to explore moving atomic models of each of the first 36 elements. Click on any element's chemical symbol to analyze it. Zoom in on the nucleus to show the closely compacted structure and note how far the electrons orbit from it. The table also provides electron shell configurations and electron potential energies. Remind students of the limitations of the modeling system: electrons follow threedimensional spherical paths, not simple cirlcular ones as depicted. Also remind them that protons and neutrons are around 2000 times more massive than electrons.
Making models of atoms is an activity many teachers use with their students. It emphasizes to the students that atoms are not twodimensional, fixed entities. Students can make the models in school or at home, and they can use a wide variety of objectsonly a few are suggested here. The models constructed have shortcomings in that they are stagnant, and the electrons may appear to be at specified, rather than most probable, distances from the nucleus.
Additional Background Information
To print out the Student Copy only, click here.
Materials
Procedure


Figure 3: Atomic model of an aluminum atom using ¼ in. pom poms as protons (white) and neutrons (black), 1/8 in. pom poms as electrons, and craft wire. 
Extensions
Students can explore the interactive online periodic table at http://www.colorado.edu/physics/2000/applets/a2.html. Each student compares the model he/she has created in the student activity with the online version of the atom and notes the successes and deficiencies of each model.
Students with Special Needs
This may be a difficult activity for students who are unable to manipulate small objects. Rather than working independently, however, students could work with partners or within small groups.
Click here for further information on laboratories with students with special needs.