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question about electron configurations

Hi.

Just hoping somebody can help on a basic chemistry question I’m stuck on. I’m doing a Bio degree and having not done A level chemistry I am taking the Intro Chem module. The question is about electron configurations:

Which is the correct electronic configuration for sulfur (S)?
a) [Ne] 3s2 3p6
b) [Ne] 3s2 3px2 3py1 3px1
c) [Ne] 3s2 3px2 3py2 3px1
d) [Ne] 3s2 3p3


So, Neon has 10 electrons and Sulfur 16, so there needs to be an extra six after the configuration of Neon. The only one that adds up to six is C but we have never specified the x and y bits of p before, we just put them as in d. However, even if I was to put C why is there 2 px orbitals, shouldn’t it be x, y and z?

Any help would be appreciated.

Thanks.
Reply 1
Olivia22
Hi.

Just hoping somebody can help on a basic chemistry question I’m stuck on. I’m doing a Bio degree and having not done A level chemistry I am taking the Intro Chem module. The question is about electron configurations:

Which is the correct electronic configuration for sulfur (S)?
a) [Ne] 3s2 3p6
b) [Ne] 3s2 3px2 3py1 3px1
c) [Ne] 3s2 3px2 3py2 3px1
d) [Ne] 3s2 3p3


So, Neon has 10 electrons and Sulfur 16, so there needs to be an extra six after the configuration of Neon. The only one that adds up to six is C but we have never specified the x and y bits of p before, we just put them as in d. However, even if I was to put C why is there 2 px orbitals, shouldn’t it be x, y and z?

Any help would be appreciated.

Thanks.

Hello,

I think i understand what ur saying...
The 2Px thing huh? well its true theres only one 2Px orbital, but "2Px" denotes that in one Px orbital, there're two ELECTRONS; hence the word "2"px

Hope that helps...
& BTW the correct answer is B & not C :smile:
Any help you need, ask away
Reply 2
hira89
Hello,

I think i understand what ur saying...
The 2Px thing huh? well its true theres only one 2Px orbital, but "2Px" denotes that in one Px orbital, there're two ELECTRONS; hence the word "2"px

Hope that helps...
& BTW the correct answer is B & not C :smile:
Any help you need, ask away



if you saw written somewhere 2px....that would mean they are talking about the px orbital in the 2nd energy level......the 2 does not represent the number of electrons in it...number of electrons are written AFTER the letter representing the suborbitals etc......like 3px2.....that means there are 2 electrons in the px orbital of the 3rd energy level.....
wat Olivia meant i think is that the options B and C say:
b)...3px2 3py1 3px1
c)...3px2 3py2 3px1

both of these are suggesting that within the P orbital are 2 px orbitals...that cant be right....because in a p-orbital, u have a px, a py, and a pz orbital....
check this out
structure of the electron shells

it'll explain it all
Reply 4
Thanks everyone. I'll have to ask them if they have made a mistake because I just can't see how it will be C because there aren't 2 px orbitals
Reply 5
Olivia22
Thanks everyone. I'll have to ask them if they have made a mistake because I just can't see how it will be C because there aren't 2 px orbitals



No there aren't two 3px orbitals but each orbital (px, py and pz) can hold upto a maximum of two electrons.

First put the electrons into each 3p orbital
3px1, 3py1, 3pz1

then start to doubly fill (spin pair) the p orbitals,
As each of the 3p orbitals are the same energy (degenerate) it doesn't matter which orbital you put the last electron into - by convention we use the x (then y and finally z).

[Ne] 3s2 3px2 3py1 3pz1 - ie answer B

If you can find a book on Physical Chemistry - read about the Aufbau principle
Hope this helps
Reply 6
Prang

[Ne] 3s2 3px2 3py1 3pz1 - ie answer B



Yeah I thought this would be the answer but B does't list the pz orbital so I think they must have just made a typing error.