Students work in groups to construct 3D molecular models. and connect the models by rubber bands representing an intermolecular force. Students a. identify the partial positive charge atoms and the partial negative charge atoms in each model that are involved in the IMF, b. calculate the difference in electronegativity between the opposite charged atoms, c. select the appropriate rubber band width to correlate with the strength of the IMF between models, d. correlate the strength of the IMF to a physical property of the liquid state of the compound - boiling point, vapor pressure, and Heat of Vaporization.