During the action of a sodium-potassium pump, 50 atp molecules were spent. predict how many sodium ions are transported across the cell membrane. a; 50 b; 100 c; 150 d; 200

I think the correct answer from the choices listed above is option C. There would be 150 sodium ions that will be transported across the cell membrane.  Each ATP molecule aids in moving 3 Na+ across the membrane. So, 50 times 3 is equal to 150.

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.