Size of atom

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KyoPhan

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Want to make sure this is a mistake or not.

General Chemistry Destroyer #244(2011)
"Destroyer says Sr+2 cation is smaller than S-2 anion, since it forms a positive ion."

Is this true? Doesn't Sr+2 have electrons in the 4th orbital level, while S-2 is just in the 3rd?

I think they were trying to compare Ca+2?


Also another question:
#249
"Which set of quantum numbers best describe a valence electron in Germanium?
a) 4,0,0,1/2
b) 4,1,1,1/2
c) 4,2, -1,1/2
d) 4,2,3,-1/2
e) 3,1,1,1/2"

I understand that B is right. But can't it also be a? Isn't A describing an electron in the 4th level, and in the s orbital. The magnetic # and the spin seems fine to me as well.

Thanks for the input.
 
Last edited:
You are overthinking this. Whenever the atom has a plus charge, it lacks electrons, therefore has a shorter diameter.

Sent from my SPH-L710 using Tapatalk
 
Also another question:
#249
"Which set of quantum numbers best describe a valence electron in Germanium?
a) 4,0,0,1/2
b) 4,1,1,1/2
c) 4,2, -1,1/2
d) 4,2,3,-1/2
e) 3,1,1,1/2"

I understand that B is right. But can't it also be a? Isn't A describing an electron in the 4th level, and in the s orbital. The magnetic # and the spin seems fine to me as well.

Thanks for the input.

If the question were asking for any electron, A is a possibility. However, it is asking specifically for the location of a valence electron.
 
For number #249. You have to remember that Germanium is in the p-orbitals so it can't be A. Anything in the p-orbital it's Azimuthal is 1. Just remember this (subshell S=0, P=1,D=2,F=3) and you should be fine.
 
So I looked up the first question because it peaked my interest and the radius of Sr2+ is 132 pm while the radius of S2- is 170 pm because of that effective nuclear charge. I guess for your DAT just assume the negative ion will always be larger (though in reality this is not always true). As for your second question I think a would be technically correct because it is a member of the 4th shell but b is the better choice because it would be more available for reaction due to smaller effective nuclear charge.

Hope that helps!
 
For number #249. You have to remember that Germanium is in the p-orbitals so it can't be A. Anything in the p-orbital it's Azimuthal is 1. Just remember this (subshell S=0, P=1,D=2,F=3) and you should be fine.

Even though this is true, it doesn't negate the fact that the s subshell still can have valence electrons.
 
Interesting. Thanks for all the input.

Even though this is true, it doesn't negate the fact that the s subshell still can have valence electrons.

That's what I think as well. For example.

When we count # of valance for like Al, don't we say that 2 of the valance are in the S orbital and 1 is in the p for a total of 3 valance?

So technically A would be okay, if it wasn't asking for the best. I didn't catch the best. I need to read carefully.
 
Want to make sure this is a mistake or not.

General Chemistry Destroyer #244(2011)
"Destroyer says Sr+2 cation is smaller than S-2 anion, since it forms a positive ion."

Is this true? Doesn't Sr+2 have electrons in the 4th orbital level, while S-2 is just in the 3rd?

I think they were trying to compare Ca+2?


Isn't A describing an electron in the 4th level, and in the s orbital. The magnetic # and the spin seems fine to me as well.

Thanks for the input.

I agree with you on this one, Sr+2 = [Kr] aka 4p6, whereas S-2 = [Ar] aka 3p6. It's doesn't make any sense to say that a 3p orbital is bigger than a 4p orbital. =/
 
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