My Notes
Categories
Two worksheets are given that walk students though visualizing and understanding solid state structure. The first worksheet focuses on metallic structure by introducing primitive, body-centered, and face-centered packing types in a cubic unit cell. Then, close packing structures are described followed by a discussion of holes in close packed or primitive packed lattices. The second worksheet introduces ionic solid structure types for the common binary salt lattices as well as perovskite and spinel structure types.
| Attachment | Size |
|---|---|
| Metallic Solids Worksheet | 28.62 KB |
| Ionic Solids Worksheet | 29.05 KB |
| This archive has the MOL files that are referenced in the worksheets as well as a few more that give a larger perspective | 17.68 KB |
A student should be able to use the Bragg equation to explain X-ray diffraction
A student should be able to identify and visualize packing types for metallic and ionic solids
A student should be able to calculate the number of atoms/ionic formula present in unit cells
A student should be able to rationalize hole sizes in lattices relative to the packed atom/ion
A student should be able to determine the coordination number for atoms/ions in lattices
Mercury Software (Free Community Version)
and/or
ICE Solid State Model Kit
This activity works really well as a dry lab yet could be adapted to be homework or an in-class activity. The given MOL files allow students to visualize the structures, however; this activity can work well with ICE model kits or even 3D printed models. NB: Mercury is a software intended for coordination compounds so metallic ions will tend to appear larger than nonmetal ions as an aesthetic quirk.
Evaluation
The responses on the worksheets are used to assess student learning.
Metallic solids: Students struggle the most with demonstrating that each packing type occupies a certain amount of available space. With guidance students perform well, and some need to be told to try the face centered packing prior to the body centered packing. Students also struggle with determining relative hole size but again with guidance tend to perform well.
Ionic solids: Students tend to do well with packing type identification. The key challenge in this activity is identifying which holes are filled and to what extent. Students tend to get the answers wrong for the perovskite and spinel structures in particular.