Solvation

Solvation is the scientific name for the process of dissolving.

To explain this process we will use the example of sodium chloride (table salt) dissolving in water.

When a crystal of table salt is added to water, the ions on the corners of the salt are vulnerable (since they are only in contact with 3 opposite ions and there is a great deal of open space around the ion where it can come in contact with the solvent.

These corners can be surrounded by water molecules which are attracted by an intermolecular attraction (in this case ion-dipole attractions).

As the ion jostles around (because everything moves a little) water molecules can “sneak” in behind further separating the chloride from the rest of the crystal. Eventually the ion can be pulled entirely aware from the crystal.

At that point the ion is dissolved.

There are are three important things to note about that moment.

The first is that the dissolved ion is not alone. Rather it is surrounded by water molecules.

The second is that the removal of this ion exposed three more to “attack” by water molecules.

The third thing to make sure that you understand is that dissolved sodium chloride is NOT sodium chloride with waters around it, it is comprised of separate ions. In other words, when an ionic solid dissolves it separates into its constituent ions. However this process CANNOT break covalent bonds. That means that when sodium sulfate dissolves, the sodium ions separate from the sulfate, but the sulfate ions do NOT separate into individual atoms. Similarly, table sugar (sucrose, C₁₂H₂₂O₁₁) dissolves, it separates into separate molecules, but not into separate atoms.