The temporal dynamics of the three dimensional hydrogen atom under the action of an external electric field is studied by using an analytic model and a numerical simulation. In the stationary case, analytic expressions for determining the evolution of angular momentum L of the Rydberg electron (RE) are obtained and significant oscillations of L are noted. Under conditions of the dynamical chaos regime stimulated by a linearly polarized microwave field, additional specific features of the evolution of L are found with the help of unification of the equations of motion and numerical calculations. The role of L in the formation of diffusion ionization of the RE is revealed.