Inter-Particle Forces

Particles can be attracted to each other by forces that cause them to clump together and become a solid.  Ionic attraction is a strong force so ionic compounds are solids at room temperature.  Molecular compounds have strong covalent bonds inside them, but they are attracted to other molecules by weaker intermolecular forces.  Non-polar molecules are attracted by the weakest intermolecular forces, so they are often gases at room temperature.  Polar molecules are attracted by the positive and negative ends of other polar molecules, so these are often liquids and solids at room temperature.  Text reference is p.90-93.
Homework:  Read p.67, 78-79, 82-83, 93 and summarize the properties of ionic and molecular (covalent) compounds.  Answer p.74 #6, p.84 #6, p.94 #6.  Download the anticipation guide for your new assignment from the unit 1 page of the grade 11 course and follow the instructions on it.