The concept of chemical fluctuations associated with electron attachment and detachment processes in the terrestrial D-region implies the existence of scale times and scale lengths over which these phenomena can be observed. An extension of Chapman's definition of scale times and scale lengths to fluctuating quantities leads to an eigenvalue problem which can be solved numerically, and for which simple analytical approximations are obtained. Two scale times associated with negative ion chemistry and with neutralization, respectively, differ by several orders of magnitude. One scale length indicates how the classical Debye length is modified by the presence of negative ions. Two other scale lengths are the spatial correspondence of the scale times. Whereas the scale length associated with negative ion chemistry ranges from 10 to 80 cm, the scale length corresponding to recombination processes ranges from 5 to 10 m.