# BOOTCAMP QUESTION

#### csulapredental

Which of the following are the correct quantum numbers for the 13th electron in chlorine’s electron configuration?

the answer was just what i regularly would of put for cl..
WHAT does this mean "13th electron"??? as in Al??????

#### 8_man

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Quantum numbers are n, l, m(sub.l), m(sub.s). Confusing, but heres the gist of it:

n represents your row number. Chlorine is in the 3rd row, so n=3. Easy.

"L" can be a range of numbers from 0 to one less than n (n=3, so L can range from 0 to 2). These numbers (0,1,2) represent the possible shells a valence chlorine electron can reside. 0=s 1=p, 2=d. Since we're dealing with the 13th electron, we're in a P orbital (so n=1)

"MsubL" represents the possible sub-shells the valence chlorine electron can reside. Numerically, MsubL=+ or -(L). Since we're looking at a P orbital, L=1. Thus, each sub-shell correlates to -1, 0, and 1. Then we fill the subshells with 1 electron each before doubling up (sounds familiar?). Since the 13th electron is the only electron in our P orbital, its gonna end up in the -1 sub-shell. So... MsubL=-1.

MsubS is easy. Its just the electron spin (what are thooseee). Who knows, and who cares. Just remember its either +1/2 or -1/2.

So, to summarize:
N = 3
L = 1
MsubL = -1
MsubS = +/- 1/2

Pretty sure you knew all this, but I'm just covering bases here. And heres my point:

Note how L and MsubL would have been completely different if we were asked to solve for the 11th or 12th electron.

Good luck.

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OP
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#### csulapredental

Quantum numbers are n, l, m(sub.l), m(sub.s). Confusing, but heres the gist of it:

n represents your row number. Chlorine is in the 3rd row, so n=3. Easy.

"L" can be a range of numbers from 0 to one less than n (n=3, so L can range from 0 to 2). These numbers (0,1,2) represent the possible shells a valence chlorine electron can reside. 0=s 1=p, 2=d. Since we're dealing with the 13th electron, we're in a P orbital (so n=1)

"MsubL" represents the possible sub-shells the valence chlorine electron can reside. Numerically, MsubL=+ or -(L). Since we're looking at a P orbital, L=1. Thus, each sub-shell correlates to -1, 0, and 1. Then we fill the subshells with 1 electron each before doubling up (sounds familiar?). Since the 13th electron is the only electron in our P orbital, its gonna end up in the -1 sub-shell. So... MsubL=-1.

MsubS is easy. Its just the electron spin (what are thooseee). Who knows, and who cares. Just remember its either +1/2 or -1/2.

So, to summarize:
N = 3
L = 1
MsubL = -1
MsubS = +/- 1/2

Pretty sure you knew all this, but I'm just covering bases here. And heres my point:

Note how L and MsubL would have been completely different if we were asked to solve for the 11th or 12th electron.

Good luck.
but if it was 14,15,15,17 it would be same....??

#### 8_man

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2+ Year Member
but if it was 14,15,15,17 it would be same....??
Well, no.

N and L stay the same, as long as we're referring to P orbital electrons.

Electron #13 and #16 will be MsubL=-1

Electron #14 and #17 will be MsubL=0

Electron #15 and #18 will be MsubL=1

And since theres two electrons per sub-shell, be sure to assign different spins for them (MsubS = + or - 1/2)

To be honest, this is beyond the scope of what the real DAT is likely to ask you. Just memorize the pattern.

(N, L, MsubL, MsubS)

N is row #
Possible L values have to be one less than N
Possible MsubL values lie between + or - L
MsubS is + or - 1/2

This is probably gonna appear ONCE on your test. No point in spending hours memorizing these details (unless you have the time, then by all means)

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#### csulapredental

no i know what the m l and all that stuff is i literally just write out the configuration and i can get everything from it.
but when they said 13th Electron of Cl i got confused.. i don't know if that means count to 13 then use that Elements configuration to get n l m or what thats what i got confused and i still don't think i get if i can or not

#### 8_man

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2+ Year Member
no i know what the m l and all that stuff is i literally just write out the configuration and i can get everything from it.
but when they said 13th Electron of Cl i got confused.. i don't know if that means count to 13 then use that Elements configuration to get n l m or what thats what i got confused and i still don't think i get if i can or not
Yep, thats exactly it. If they ask for the 5th electron of chlorine, you just refer to the 5th element on the periodic table for your quantum numbers. The only exception is that your N value is representative of chlorine.

OP
C

#### csulapredental

Yep, thats exactly it. If they ask for the 5th electron of chlorine, you just refer to the 5th element on the periodic table for your quantum numbers. The only exception is that your N value is representative of chlorine.
ok so was i right by going to Al when they asked for 13th electron of chlorine??

#### 8_man

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ok so was i right by going to Al when they asked for 13th electron of chlorine??
Yup, you got it.

OP
C

#### csulapredental

whats the point of them even saying 13th from chlorine lol... if they said 13th from uranium it would of still been the 13th....? Al....??

#### 8_man

##### Achievement Unlocked: Dental School
2+ Year Member
whats the point of them even saying 13th from chlorine lol... if they said 13th from uranium it would of still been the 13th....? Al....??
The point is for you to get it right so you can get a pretty score and go to dental school.