1. The outermost shell of electrons for each different
element should be represented by a different colored
pipe cleaner.
2. The valence electrons of each different element should
be represented by a different colored bead.
3. For beads (electrons) contained in covalent bonds, the
beads must be contained in both the pipe cleaner “shells”
of the atoms forming the bond.
4. Each covalent bond must contain 2 or a multiple of 2
beads.
5. For diatomic molecules, different colors of pipe cleaner
and beads should be used for each atom.