# How does ion size affect conductivity?

Apr 7, 2014

In general, smaller ions have greater conductivity than larger ions.

#### Explanation:

Small ions have small areas. There is less resistance as they move through the solution.

For example, in molten salts, the conductivity of ${\text{Li}}^{+}$ is greater than that of ${\text{Cs}}^{+}$.

Small ions have high charge density.

In aqueous solutions, this gives them a large hydration shell that moves with them.

For example, hydrated ${\text{Li}}^{+}$ ions are larger than hydrated ${\text{Cs}}^{+}$ ions.

Thus, aqueous solutions of lithium salts have lower conductivities than those of cesium.