Ionic Bonding Models and Reality

In this section, we have developed a model for ionic bonding. The value of a model is in how well it accounts for what we see in nature (through experiments). Does our ionic bonding model explain the properties of ionic compounds, including their high melting and boiling points, their tendency not to conduct electricity as solids, and their tendency to conduct electricity when dissolved in water  

We modeled an ionic solid as a lattice of individual ions held together by coulombic forces that are nondirectional (which means that, as you move away from the center of an ion, the forces are equally strong in all directions). To melt the solid, these forces must be overcome, which requires a significant amount of heat. Therefore, our model accounts for the high melting points of ionic solids. In the model, electrons are transferred from the metal to the nonmetal, but the transferred electrons remain localized on one atom. In other words, our model does not include any free electrons that might conduct electricity 

Use the ionic bonding model to determine which has the higher melting point, NaCl or MgO. Explain the relative ordering. 

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