Different types of model are used to represent giant ionic structures.
Remember that the lattice arrangement is giant - for example, a single grain of salt may contain 1.2 × 1018 (1,200,000,000,000,000,000) ions. The lattice arrangement continues in three dimensions. This is why solid ionic compounds form crystals with regular shapes.
Each has its advantages and limitations. For example:
Use the three-dimensional ball-and-stick model to show that the formula of sodium chloride is NaCl.
The model shows equal numbers of sodium ions and chloride ions, so the formula is NaCl.