Which is the term for the group of proteins that organizes and condenses long strands of dna into tight coils?

That would be histones, the proteins that make up nucleosomes. Nucleosomes are the basic unit of the packaged DNA-protein complex found in cell nuclei, also known as chromatin.

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.