Ionic Compound Models

Having grade nines understand ionic charges, ionic bonding and the resulting chemical formula can be challenging.  To help my students visualize and understand how ionic binary compounds are formed, I created styrofoam and velcro balls as models.  I used the fuzzy side of the velcro dots for the metals and the hook side for the nonmetals so that the students could only "form" ionic bonds.  They could "see" the amount of electrons to transfer from the metal to the amount taken by the nonmetal.  They could "see" the resulting model in the proper ratio that is formed.  I used to use mini marshmallows and toothpicks or styrofoam balls stuffed in coloured balloons joined with toothpicks, but it did not help students see the ratio needed to bond.  This was more straightforward and far easier for them to understand.  From this process, it was much more clear when we wrote simple ionic charges and simple formation reactions.