Page 310 - MODERN ELECTROCHEMISTRY

246 CHAPTER 3

Fig. 3.14. The total charge on the ionic cloud
is just equal and opposite to the charge on the
central ion.

How is this equal and opposite charge of the ion atmosphere distributed in the
space around the central ion? It is seen from Eqs. (3.35) and (3.36) that the net charge
in a spherical shell of thickness dr and at a distance r from the origin is

Thus, the excess charge on a spherical shell varies with r and has a maximum value
for a value of r given by

Since is finite, Eq. (3.41) can be true only when

or