However, there are other requirements on ψ that lead to it being a “ well-behaved ” wave function. For
example, since the integral shown above must equal 1.00 … , the wave function cannot be infi nite.
As a result, we say that ψ must be fi nite . Another restriction on ψ relates to the fact that there can be
only one probability of fi nding a particle in a particular place. As an example, there is only one prob-
ability of fi nding an electron at a particular distance from the nucleus in a hydrogen atom. Therefore,
we say that the wave function must be single valued so that there results only one value for the prob-
ability. Finally, we must take into account the fact that the probability does not vary in an abrupt
way. Increasing the distance by 1% should not cause a 50% change in probability. The requirement
is expressed by saying that ψ must be continuous . Probability varies in some continuous manner, not
abruptly. A wave function is said to be well behaved if it has the characteristics of being fi nite, single
valued, and continuous.