Consider the example for Sc where the 3d orbital is not filled but the 4s is.

The fact is that 4s orbitals have a lower energy than the 3d orbitals, which therefore means that 4s orbitals will in fact fill up first. Any electrons that are lost from Sc (most likely) will come from the highest energy level, or the 3d.

This is origin of the notation you are using, and you can apply the same reasoning to all the other elements you have listed.

Consider the example for Sc where the 3d orbital is not filled but the 4s is.

The fact is that 4s orbitals have a lower energy than the 3d orbitals, which therefore means that 4s orbitals will in fact fill up first. For example, any electrons that are lost from Sc causing it to ionize (Sc$^+$) will come from (most likely) the highest energy level, or 3d.

This is origin of the notation you are using, and you can apply the same reasoning to all the other elements you have listed.