00:01
So for part a, helium has two electrons, meaning that the total spin s can either be zero.
00:17
That means single it or it could be one, which means triplet.
00:22
So according to the first hertz rule, excited states, excited states, which are triplet, will have lower energy, lower energy, then the same excited states, then the same excited states, which are singlets, fine.
01:16
So, zero means singlet and one means triplet.
01:21
Fine.
01:22
So according to the houn's rule, excited states that are in triplet, which are triplet, will have a lower energy, then the same excited states which are singlets, right? so then moving on, we have part b.
01:42
So part b is that carbon in the last subshell, in last subshell, have, sorry, has two, electrons meaning s is either equal to 1 or 0 and l is equal to 0 1 or 2.
02:18
So using first one's rule the total spin s total spin s is equal to 1 and the state is symmetric state is symmetric now we need to find anti -smetric position bar of weight function for that we have l is equal to 0 and l is equal to 2 that are symmetric so that leads us with l is equal to 1 that would be nt symmetric or a symmetric fine so the total angular momentum the total angular momentum j with the s is equal to 1 and l is equal to 1 so j could be 0 1 2 so possible ground space for carbon are 3 p 2 3 p 1 and 3 p 0 next moving forward we have part c so for part c boron has 1 electron in 2 p sub now the ground states will have total angular momentum.
03:58
J is equal to l minus s.
04:01
For l is equal to 1 and s is equal to 1 by 2 from the previous task.
04:07
We have j is equal to 1 by 2 and the ground state for boron is 2p 1 by 2.
04:14
Next we have part d.
04:19
So ground state of carbon, the ground state of carbon, is s equal to 1, l equal to 1.
04:31
And because of that, we have three possibilities for total angular momentum...