# quick g-chem question; quantum numbers

#### system7

7+ Year Member
this is question #208 from 2009 destroy

which set of quantum numbers best describes a valance electron in Germanium?
a) 4,0,0,1/2
b) 4,1,1,1/2
c) 4,2,-1,1,2
d) 4,2,3,1,2
e) 3,1,1,1/2

the answer they have given is b. What i'm getting is 4,1,-1,1/2
since the 4p valence electron is in the first orbital of 4p, it should have a magnetic quantum number of -1. somebody please explain this to me if i'm not getting this right. thanks

#### Maygyver

10+ Year Member
5+ Year Member
this is question #208 from 2009 destroy

which set of quantum numbers best describes a valance electron in Germanium?
a) 4,0,0,1/2
b) 4,1,1,1/2
c) 4,2,-1,1,2
d) 4,2,3,1,2
e) 3,1,1,1/2

the answer they have given is b. What i'm getting is 4,1,-1,1/2
since the 4p valence electron is in the first orbital of 4p, it should have a magnetic quantum number of -1. somebody please explain this to me if i'm not getting this right. thanks

I believe the magnetic quantum number can be 1, 0, or -1. I'm not sure if there is any differing in which ones fill up as far as that goes. I think you should know that it is b due to the first 2 numbers (4 and 1) and then just knowing that the p shell can have magnetic quantum numbers of -1 to +1.

#### SPR1624

10+ Year Member
If the numbers are listed as n,l,ml,ms............

Wouldn't the correct quantum numbers be....

4,3,-3 to 3, and + or - 1/2? in the same order listed above?

#### UCB05

If the numbers are listed as n,l,ml,ms............

Wouldn't the correct quantum numbers be....

4,3,-3 to 3, and + or - 1/2? in the same order listed above?
n = level = 4
l = sublevel; s=0, l=1, d=2
ml = angular momentum states = -l to l
ms = spin = 1/2, -1/2

A p orbital is l=1

As for the op, simple answer is that the exact value of ml is somewhat arbitrary, because who's to say what exact orientations in space represent px, py, and pz. Basic info to understand is that the ml of a p orbital could be 1, 0, or -1. Beyond that you just have to make sure the other quantum numbers make sense.

#### system7

7+ Year Member
i guess i was getting confused because i thought every valence electron had one exact value for ml otherwise i know that for any p subshell, ml could only be -1, 0, or +1, for d it could only be -2,-1,0+1,+2 etc. anyway, thanks for the quick replies.