Why do ionic compounds have high melting points?

Ionic compounds have high melting points due to the strong electrostatic forces of attraction between their positive and negative ions.

Ionic compounds are formed when a metal reacts with a non-metal. They consist of a lattice structure with alternating positive and negative ions. These ions are held together by strong electrostatic forces of attraction, also known as ionic bonds. The strength of these bonds is what gives ionic compounds their high melting and boiling points.

To melt an ionic compound, you need to provide enough energy to overcome these strong forces of attraction and break the ionic bonds. This requires a large amount of heat energy, hence the high melting point. The same principle applies to boiling these compounds. The stronger the forces of attraction, the more energy is needed to break the bonds, and the higher the melting and boiling points will be.

For example, consider sodium chloride (NaCl), a common ionic compound. It has a melting point of 801°C, which is considerably high. This is because sodium (Na) and chloride (Cl) ions in the compound are held together by strong ionic bonds. To convert solid sodium chloride into a liquid or gas, a significant amount of heat energy is required to overcome these bonds.

In summary, the high melting points of ionic compounds are a direct result of the strong electrostatic forces of attraction between their ions. These forces create robust ionic bonds that require substantial energy to break, leading to high melting and boiling points.