In an attempt to explain the unique behavior of small ions in polar solvents, two models have been proposed that attribute different phenomena to solvent response and solute or ion displacement. The first model, often referred to as the solventberg model, maintains the classical view of Stokes law but introduces an "effective" ionic radius that arises from solvation. In this model, with solvent molecules considered bound to the ion, the radius of the solvated complex is equivalent to a Stokes radius. The other model is the dielectric friction model, which has been developed over several decades by Born, Fuoss, Boyd, and Zwanzig, with a comprehensive theoretical framework established by Hubbard and Onsager. This model aims to describe the dielectric response of the solvent when perturbed by the motion of an ion. As the ion moves away from its initial position, where the solvent is polarized according to the electrostatic field generated by the ion, the solvent polarization does not immediately equilibrate with the new position of the ion. This leads to a relaxation process and subsequent dissipation of energy in the form of dielectric (or extra) friction. The dielectric friction is inversely related to the ionic radius. As a result, the friction coefficient exhibits a minimum with increasing ionic radius in both models.