Which method would be the best for separating the salts for seawater

The best way to separate salt to seawater is the boil the seawater and at the end, you would be left with salt

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.