Final answer:
Charge balance is maintained by keeping structural sites unfilled through the process of maintaining an equal number of positive and negative charges.
Step-by-step explanation:
Charge balance is maintained by keeping structural sites unfilled through the process of maintaining an equal number of positive and negative charges. This means that for every positive charge, there is a corresponding negative charge to balance it out. For example, in an ionic compound like sodium chloride (NaCl), the sodium ion has a positive charge and the chloride ion has a negative charge, resulting in a neutral overall charge for the compound.