Ice that contains a small amount of dissolved air is an example of what type of solution?

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.

Idon't mean to be a smart alec, length of atoms' bonds is the simplest way to define it.