This modeling activity can also be used as a supplementary
lesson for students who already have a working knowledge of
the nature of covalent bonds, either to reinforce understanding
or to provide variety in a series of lessons. A suitable starter for
the lesson would be to present students with the formulas of a
number of covalent molecules and ask them to choose one to
draw a Lewis diagram of. As with the previous approach, this
activity can be easily differentiated through matching the choice
of molecule to the abilities of the students (see Supporting
Information, notes for instructors).
The students are then presented with the model making
activity. For students with a good understanding of the
chemistry it is possible to present them with the materials,
explain what each represents, and allow them to construct their
models through a process of trial and error. Students with less
secure understanding will need some guidance, with the teacher
leading the students through the development of some “rules”
through discussion. Typical rules arising from such discussion
include the following: