More and more questions that get more and more difficult to answer. Most of these answers will not be obvious to you for some time to come but let's go ahead and try to present the basic framework of how this works. Let's look at the Order of Filling now as this determines the entire framework of atomic structure and periodic table placement. Read the following bullets and refer back to the sample Quantum Number Diagram. No two electrons can have the same four quantum numbers.
Electrons remain unpaired in spin as long as is possible.
Said another way, electrons entering a sub-level containing more than one orbital will be spread out over the available orbitals with their spin in the same direction. Again, many questions with difficult answers. 1s 2 would symbolize the element Helium. 2 2s 1 would symbolize the element Lithium. 1s 2 2s 2 would symbolize the element Beryllium.