Q. Which one of the following sets of quantum numbers could be those of the distinguishing (last) electron of Mo?
A. n = 4, l = 0, ml = 0, ms = +1/2
B. n = 5, l = 1, ml = 9, ms = -1/2
C. n = 4, l = 2, ml = -1, ms = +1/2
D. n = 5, l = 2, ml = +2, ms = -1/2
Answer: n = 4, l = 2, ml = -1, ms = +1/2
