The atomic model you have been using so far is nice and basic, and simple to understand and apply. No awkward, inconsistent rules to worry about.
But it has limitations.
These limitations stop it from being useful beyond the first 20 elements, and for concepts that you are going to be using from this level.
In the advanced model you’ll discover that atoms are not that 2 dimensional, “solar system” model. You’ll learn that electrons exist in orbitals within the shells, and that each shell can accommodate a different number of electrons.