quantum numbers- azimuthal number?

[diene]

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I am a a little confused about the azimuthal value.

Lets say that I am trying to find a set of quantum numbers for bromine.
n = 4 so L could be 0...n-1 which means that L could be 2 or 3? ; s= 0 p = 1 d = 2 f=3
but if L was 2, then that would imply a d orbital and if 3 it would be f orbital? However, the value of L should be 0 or 1?

When I look at ml. I would use -L....L to determine the value so it would be between -1 and 1

This n-1 is confusing me..can someone explain this?
Thanks

 

[jaymin8]

When you go to the fourth shell, you see, in that shell, there are S,P, and D orbitals present. So for Bromine, you see that it is on the fourth shell/row. So n is four. L is the subshell it is in. You know it is in the P and give it the number 1. When Chad does the n-1 rule, he is simply stating that the 4th shell contains S,P,D, and F orbitals as you can see on the 4th row. After figuring out what subshell Bromine is in (P orbitals so you use L=1), then you move to the ml. The ml is the specific orbital. This is where you draw the little squares and fill in the electrons. As you know there are three squares for the P orbital which can hold up to 6 electrons. Each square has a number (-ml to ml). Because there are three squares in the P orbital, you number them -1,0,1 and fill in the electrons in the squares. There are five electrons in the P orbital for Bromine and you see that the last electron lands in the square 0. Therefore, the ml is 0.
I hope the last part makes sense. If not tell me and I can upload a picture of what I am trying to say.

 

[diene]

Okay, that makes sense. So the n-1 rule was general statement, correct? For every problem, I don't have to do "n-1." I can figure out the L value by using the s=0 p=1 d= 2 etc rule?
For Ml, I drew out what you stated and it makes sense. But the rule is the it can be between -L...L. So if I was given the choice of Ml = 1, it would be okay, right? Even though based on the drawing it should be in 0? does the fact that it can be -1,0,1 have something to do with hybridization?

 

[jaymin8]

Exactly. the N-1 rule is the MAXIMUM number basically. The ml is zero and can only be zero because when you fill the electrons you see it fills each square first before putting the second one in. For Bromine the electron is in the 0 square. If you do Se (the one before Bromine, which has one less electron), then that electron would fall in the -1 square. If you do Kr( the one after Bromine, which has one more electron), then that electron would fall in the +1 square.

 

[diene]

The L stuff now makes sense, but I am bit confused on Ml now lol..why is it -L....L

There was a question in topscore:
find the quantum numbers for the highest energy electron in flourine.
n= 2 L= 1 ml = 1
is ml 1 instead of 0 because they are asking for the "highest energy" electron? is that different than just asking for quantum numbers of flourine? if it was just the quantum numbers, ml = 0?

Also, for bromine, in chad's explanation for why choice C. [4,1,-2,+1/2] can't be it. "To be in an s or p subshell, l=0 (s) or l=1 (p) so so far choices A or C could work. But ml is restricted in being an integer between –l and +l. This rules out choice C as -2 is not between -1 and 1. "

Why is he saying that L can be 0 or 1..i thought it would only be 1?

 

[SN1]

The L stuff now makes sense, but I am bit confused on Ml now lol..why is it -L....L

There was a question in topscore:
find the quantum numbers for the highest energy electron in flourine.
n= 2 L= 1 ml = 1
is ml 1 instead of 0 because they are asking for the "highest energy" electron? is that different than just asking for quantum numbers of flourine? if it was just the quantum numbers, ml = 0?



Why is he saying that L can be 0 or 1..i thought it would only be 1?

Because the range of L(azimuthal) is (0, [n-1]) and since n=2 then your L value can be 0 or 1


Don't get confused by a question asking for a POSSIBLE set of quantum numbers for an ELECTRON VS a question asking for set of quantum numbers for a VALENCE electron

 

[SN1]

can you type the original question for the Br?

 

[diene]

In the flourine example, one of the choices has L=0 but the answer is the choice with L= 1, so does that have to do with the fact that they are asking for the "highest energy electron"?

Here is the bromine question
Which of the following is a possible set of quantum numbers [n,l,ml,ms] for a valence electron in bromine?

since they are asking for "a valence electron" it could be in the s or p orbital, right? because bromine has 7 valence electrons some of which are in the s orbital.

 

[SN1]

In the flourine example, one of the choices has L=0 but the answer is the choice with L= 1, so does that have to do with the fact that they are asking for the "highest energy electron"?

Here is the bromine question
Which of the following is a possible set of quantum numbers [n,l,ml,ms] for a valence electron in bromine?

since they are asking for "a valence electron" it could be in the s or p orbital, right? because bromine has 7 valence electrons some of which are in the s orbital.

Ahhh I remember this question now. I actually was wondering about them too.

For your topscore question, since they ask for "the highest energy" that means valence electron and for fluorine you have:
2s^2 and 2p^5 so yes you would pick L value that corresponds to P

However, in the case of chad's quiz, I do remember him asking the same type of question and there were TWO possible answers and I believe the right answer was the one indicating the S orbital.

Honestly I doubt you would encounter a question that list 2 possible answers on the DAT. BUT if you do get one of these, I would pick the one that is on the outtermost.

so if you have s and p I would pick p.

I believe there is the same question on kaplan blue book right?

 

[diene]

I am not sure which KBB problem you might be referring to?

As for the topscore one, the answer is [2,1,1,-1/2] ml is 1 because they are asking for the highest energy electron, right? because it could have easily been a valence electron in -1 or 0? but the fact that it's the highest leads one to choose the one in ml = -1?

Haha, I am probably getting too involved with these type of questions, but once you get stuck on some small details, it's hard to move on lol

 

[SN1]

I am not sure which KBB problem you might be referring to?

As for the topscore one, the answer is [2,1,1,-1/2] ml is 1 because they are asking for the highest energy electron, right? because it could have easily been a valence electron in -1 or 0? but the fact that it's the highest leads one to choose the one in ml = -1?

Haha, I am probably getting too involved with these type of questions, but once you get stuck on some small details, it's hard to move on lol

wait it wasn't kbb, it is actually on dat destroyer I am sure there was one question exactly like what you are asking.

ml is 1 because the range for ml is -L to L NOT because it is the highest energy electron.

And since your highest energy electron is in the P orbital, then your L must be 1 and THEREFORE your ml can be -1,0, or 1

 

[diene]

haha yeah #38 in the 2011 version..I seem to get all of these types of questions right, but I wasn't quite understanding the whole logic.
based on what the person above you said:
"The ml is zero and can only be zero because when you fill the electrons you see it fills each square first before putting the second one in. For Bromine the electron is in the 0 square. If you do Se (the one before Bromine, which has one less electron), then that electron would fall in the -1 square. If you do Kr( the one after Bromine, which has one more electron), then that electron would fall in the +1 square."

From that it seemed like ml couldnt be -1,0,1...it had to be 0?

 

[SN1]

haha yeah #38 in the 2011 version..I seem to get all of these types of questions right, but I wasn't quite understanding the whole logic.
based on what the person above you said:
"The ml is zero and can only be zero because when you fill the electrons you see it fills each square first before putting the second one in. For Bromine the electron is in the 0 square. If you do Se (the one before Bromine, which has one less electron), then that electron would fall in the -1 square. If you do Kr( the one after Bromine, which has one more electron), then that electron would fall in the +1 square."

From that it seemed like ml couldnt be -1,0,1...it had to be 0?

I am not sure what you mean but here is an explanation I can give.

Let say I have valence electron in which the highest energy shell is a "P" subshell.

so this means my L = 1
and since you can have 3 KINDS of p orbitals then you can have 3 POSSIBLE ml values that is -1, 0, or 1

and that is exactly why the range for ml is written by the formula (-L,L)

Not sure if I am answering your question though

 

[diene]

thanks I gotcha 😀 just one more thing...could there be a case where we would have to choose one ml over the other?

 

[SN1]

thanks I gotcha 😀 just one more thing...could there be a case where we would have to choose one ml over the other?

In my opinion, the DAT will be much more straight forward(although I haven't taken it yet). When are you taking the DAT and are you applying this year?

 

[diene]

June 20th *hides* and yes..hopefully I will be applying this year lol
What about you?

I hope it will be straight forward, but the test makers can be quite evil haha!

 

[SN1]

June 20th *hides* and yes..hopefully I will be applying this year lol
What about you?

I hope it will be straight forward, but the test makers can be quite evil haha!

Wow that is very soon I am graduating in spring of 2014 so I am applying in 2013. However, I am taking the DAT this september so I have one less thing to worry about when I apply next year.

good luck to ya.