When an ionic compound melts,the structure of the crystal lattice breaks down and the ions must be able to slip past each other.Using electrostatic potential energy as a guide,which listing of ionic compounds is in order of increasing melting point?

Question

Quizplus · Accepted Answer

The electrostatic potential energy between ions in an ionic compound increases as the charge of the ions increases and as the distance between the ions decreases. Based on this, we can predict that the compound with the smallest, most highly charged ions (NaF) will have the lowest melting point, while the compound with the largest, least charged ions (AlF3) will have the highest melting point. This rules out choices A, B, and D. Choice E is also incorrect because it has AlF3 with a lower melting point than NaF, which is not possible. Therefore, the correct order is C: NaF < MgF2 < AlF3.

When an Ionic Compound Melts,the Structure of the Crystal Lattice