Calculate the energy of a photon that has a frequency of 5.0 × 10^11 Hz

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.

Ibelieve its because the stove is a cleaner burning fuel

Just took the quiz on edgenuity and the correct answer is "c.  4.54 x  10–12  j"