00:01
In this video, we want to determine which sets of quantum numbers are allowed and which are not allowed.
00:06
So we have some rules.
00:07
The easiest rule to, you know, eliminate some at first glance is if we have m sub s, which is the electron spin, it can only take on the values of positive one -half or negative one -half -by convention.
00:19
So any other value is just wrong, regardless of whatever else is true of the quantum numbers.
00:24
So if we look at the m -sub -s values, we see this negative one here for choice d.
00:28
So that's not going to be allowed.
00:31
All right, everything else, the m sub s is allowed.
00:33
So now we can go back and look at the principle and sublevel.
00:38
So we know that the principle level n can be one, two, three, and so on.
00:43
So any whole number, one or greater.
00:46
And then l has to be between zero and n minus one, whole numbers.
00:55
So let's look at the n and l combinations, make sure that we have positive whole numbers for n, and that l doesn't exceed n minus 1.
01:02
So for a, because n and l are the same, that's invalid...