Weeks 2,3,4 Achieve #21

[raynebunado]

Hi! Can someone please explain the logic of the first part of Achieve's HW #21, n = 3 has how many electrons? I am confused why it isn't 2 e- since l = 0, assuming it is not explicitly defined. Thanks so much!

[Sadhana Jeyakumar 2J]

When n =3, l can have values of 0, 1, and 2. We know that l = 0 corresponds to the s orbital, l = 1 corresponds to the p orbital, and l = 2 corresponds to the d orbital. The s orbital can hold 2 electrons, the p orbital can hold 6 electrons, and the d orbital can hold 10 electrons. Adding these values ( 2 + 6 + 10 ), we get that 18 electrons could have n = 3 as their principle quantum number.

[Erika Li 1E]

When n=3, then l can take on the values from 0 to n-1. That means l can have the values of 0, 1, or 2. When l=0, that corresponds to the s-subshell. Since there is 1 orbital in the s-subshell, and each orbital holds 2 electrons, the s-subshell holds up to 2 electrons. When l=1, that corresponds to the p-subshell. Since there are 3 orbitals in the p-subshell, and each orbital holds 2 electrons, the p-subshell holds up to 6 electrons. When l=2, that corresponds to the d-subshell. Since there are 5 orbitals in the d-subshell, and each orbital holds 2 electrons, the d-subshell holds up to 10 electrons. This results in 2+6+10=18 electrons when n=3. Hope this helps!

[Jessica Cornelia Hongarta 1G]

Hey! So, the question only states n=3. There are 3 possible l/subshell (s, p, and d) for n=3. We know that the maximum number of electrons for s-subshell is 2, for p-subshell is 6 and for d-subshell is 10. So, you need to add all of that (2+6+10. The total number of electrons for n=3 is 18 electrons.

Hope this helps!

[Kurosh Zamiri 1I]

Hi! If n=3, then this means that the value of l can be anything up to n-1. In this case, l could be 0,1, and 2. When l=0, this corresponds to the s sub-shell. When l=1, this corresponds to the p sub-shell. Lastly, when l=2, this corresponds to the d sub-shell. We know that the s sub-shell has 1 orbital, the p sub-shell has 3 orbitals, and the d-sub-shell has 5 orbitals, and each orbital can hold 2 electrons. Therefore, using the equation 1(2) + 3(2) + 5(2), we get 2+6+10 which is a total of 18 electrons! Hope this helps!

[Rena Wu 3E]

Hey! Since the question doesn't specify the angular momentum # (l) or magnetic quantum # (ml), the number of electrons in your answer can come from the 3s, 3p, and 3d subshells. Since the 3s subshell has 1 orbital, there are 2 possible electrons coming from that subshell. Likewise, there are 6 possible electrons from the 3p subshell and 10 possible electrons from the 3d subshell. In total, that would be 2 + 6 + 10 = 18 possible electrons when n = 3. Hope this helps!

[Genelle Marcelino-Searles 2G]

Hello!
I think you confused the subshell with the amount of electrons. N=3 has three subshell possibilities, 0,1,2 (s,p,d). We would add the amount of orbitals in each of these together in order to get 9, (s having 1 orbital, p having 3, and d having 5). Since each orbital can fit 2 electrons, we would multiply this by two in order to get 18.