This reaction uses 24.1 g of copper(I) sulfide. Determine the volume of sulfur dioxide gas that would be collected at 237°C and 10.7 atm.
___Cu2S (s) + ___O2 (g) → ___Cu2O (s) + ___SO2 (g)

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.

Bis the answerhope it !