Achieve #21

[905574994]

Hi,

Could someone please help with this question:

How many electrons in an atom could have these sets of quantum numbers?

part a) n=2

part b) n=4 l=3

part c) n=6, l=1, ml=-1

I got part a but I'm confused on parts b and c.

Thank you!

[RossLechner3E]

For part b you cant start by finding the possible magnetic quantum numbers, ml, since those are the only ones not given. So for l=3 ml could be -3,-2,-1,0,1,2,3. This would give 7 unique orbitals and since each orbital can hold two electrons, spin up and spin down there would be 14. For c we have all the information for the orbital so it is only 2.

[Eszter Kovacs 1A]

Hi,

For b) given that n=4 and l=3 you have to look at the orbitals of the 4f subshell, for a f subshell the magnetic quantum number can be ml= -3,-2,-1,0,+1,+2,+3, so it has 7 orbitals.

[Vicky Tong 3E]

Hi! To add more information to why part c is 2 is because when n,l, and ml are specified, a specific orbital is identified. Therefore, there will only be 2 electrons because an orbital can only hold 2 electrons.

[Elena Chan 2L]

Hi,

For any value of ml, you can have 2 electrons per every sub-orbital. Since b has an l value of 3, that correlates to the f-subshell which has 7 orbitals and 14 electrons (2 electrons for every 1 orbital) that can contain those quantum number. For c, you have specified a ml value which makes it only 2 electrons since ml=-1 for the p-orbital correlates to Px orbital which can contain 2 electrons. Hope this helps!

[LaurenAkason2A]

Hi! Part b would result in 4f14, so that means there would be 14 electrons. We know this because n=4 and l=3 which means it is in the f orbital. Part c would be 2 electrons because when you are given an ml value there are only 2 electrons in an orbital that can have that value.

[Celine Khuu 2F]

It is important to remember that no two electrons have the same four quantum numbers (n, l, ml, ms). So, looking at part b, we are given n = 4 and l = 3. We know that for l = 3, there can be 7 values for ml, which are: -3, -2, -1, 0, 1, 2, 3. This means that there are 7 orbitals. Remember that 2 electrons can occupy one orbital, and each can either have an ms value of -1/2 or +1/2. Therefore, in total, there would be 14 electrons.

[Matt Vargo 2D]

Just as a general rule for part c, an orbital can only contain two electrons. So if a question is ever asking how many electrons can be in a specified magnetic quantum number (ml) while also giving its specific n and l values, then the answer is always two electrons.

[HaleyC 2F]

Since it says ml=-1, it would be in the px orbital which can hold only 2 electrons.

[HaleyC 2F]

Since it says ml=-1, it would be in the px orbital which can hold only 2 electrons.

[Saebean Yi 3E]

b) with the information given, you know that it correlates to the 4f subshell. The 4f subshell has 7 orbitals, so there can be 14 total electrons that corresponds to the information given (since 2 electrons per orbital). Since we are not given ml, all 14 of the electrons could have these quantum numbers.

c) you can disregard all the information really except for ml. It's still important to recognize that the information given corresponds to the 6p subshell, but since ml is more specific of a quantum number than n or l, we really only need to look at ml. ml is a single orbital, and since one orbital can hold 2 electrons, there are 2 electrons that could have these sets of quantum numbers.

[Hannah Thornton 1F]

for b, since you know that l=3, that means ml must be -3, -2, -1, 0, 1, 2, 3. this gives 7 orbitals, and since each orbital can hold 2 electrons, that means 14 electrons.

for c, we have a given ml value so the answer would be 2 since it is once specified orbital with 2 electrons.