Cuantas moleculas de HCl hay en 10.1g de HCl

Yes you are correct use the scientific method

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.

Fine out you self hx