My textbook has a figure like the one above.
But for some reasons it doesn't always work. Like for example the electron configuration for Cadmium. According to my facits:
I don't understand why the 3d^10 comes before the 4s^2
According to the figure, that shouldn't be the case?
I remember a long time ago I heard that the figure above does not count for transition metals? Or was it ions? I don't remember it exactly and my textbook gives me nothing, so could somebody please verify that and give me some explanation?
When can I use the figure above and when can't I? And if I can't use the figure above, what other methods do I use?