ION EXCHANGE is the swapping of a reversible interchange of charged particle ions with those of a like charge. The resins ultimately function this way due to the functional groups, which are permanently bound within the polymer matrix of the resin. The charged ions are then more or less programmed to then bond with ions of an opposing charge. The opposed charged ions are then delivered through the application of the resin base until equilibrium occurs. As a rule of thumb, the greater the size and/or valency of an ion, the greater affinity it will have with ions of an opposing charge.