To account for this additional complexity, two new quantum numbers need to be considered. The QN n has the same interpretation as it did in the Bohr model. It defines the distance from nucleus at which an electron s density probability is at a maximum. In some texts these shells are denoted by letters. The QN m l depicts the spatial orientation of a given class of orbitals defined by QN l .
Nodal planes are flat and extend infinitely in two dimensions.
Radial nodes are spherical in nature, centered on the nucleus and with some radius r . The number of nodes, and hense the complexity of the orbital, increases as the principle quantum number increases. For a look at the hydrogen atom wave functions, check out the following webpage. The higher the probability of finding an electron close to the nucleus, the greater its orbital penetration is said to be. See Figs 1.7 and 1.9 in the text.