Tuesday, November 9, 2010

Trimester 1 Exam Review:

Question #19:
Give three distinct examples of quantum number combinations that cannot occur, and explain why they are impossible. Each example should illustrate a separate violation.

Example A)
(0,0,3,-1/2) - This combination cannot exist because the n #(the energy level) cannot be 0. 

Example B)
(3,3,1,1/2) -  This combination doesn't exist because it has the n and the l numbers the same.This is not possible.

Example C)
(1,2,1,1/2) -  This combination doesn't work because of the n and l numbers. The second number (l=2) represents a d orbital, but level (n=1) does not have a d orbital, making these quantum numbers impossible. 


  1. Good job, but you may want to add a bit more about example b. This combination doesn't exist (3,3,1,1/2), because the energy level is 3, and the l value is 3 as well. The l stands for the type of orbital. For l=3, it is called the f orbital. In the third energy level it only goes up to the d orbital where l=2. Therefore this does not exist. This applies any time the energy level and type of orbital (1st and 2nd places in the quantum combination) are the same. All your examples were good, but just need a little bit more explanation.

  2. Good job emily, the only thing i would add is to say the reason the n and l values cant be the same is because to the l values are ( 0 through n-1). For example (3,3,1,1/2) the l values for the 3rd energy level can only be 0,1,2.

  3. I would also add that mL cant be greater than L and that mS can't be anything other than +1/2 and -1/2