00:01
Consider a system of two electrons each with l equals 1 and s equals 1 half.
00:06
What are the possible values of the quantum number for the total angular momentum? l is equal to l1 plus l2.
00:13
So that means little l is l1 plus l2.
00:20
And then we get l1 plus l2 minus 1 dot dot and the absolute value l1 minus l2.
00:34
So the possible values are 1 plus 1, 2, 1 plus 1 minus 1, 1, and 0.
00:51
For part b, what are the possible values of a quantum number s? so similarly, s is equal to s1 plus s2, s1 plus s2, s2 minus 1, dot, dot, s1 minus s2.
01:11
So this would be 1 half plus 1 half, which is 1 and 1 half minus 1 half to 0.
01:28
Part c, find the possible quantum numbers, j for the combination.
01:37
Okay, so little j is l plus s.
01:42
L plus s minus 1 dot dot dot l minus s.
01:52
But now we need to do combinations.
01:55
So l is 2.
01:58
S is 1.
02:00
That means j is 3 to 1.
02:04
L is 2.
02:06
S is 0.
02:11
J is 2.
02:13
L is 1...