Asymmetric Carbon: Why Treat - Sign as Group?

  • Thread starter Thread starter gracy
  • Start date Start date
  • Tags Tags
    Carbon
Click For Summary

Discussion Overview

The discussion revolves around the concept of asymmetric carbon atoms in organic chemistry, specifically addressing the treatment of negative and positive charges as groups or atoms. Participants explore the implications of charge on the asymmetry of carbon atoms and the criteria for determining asymmetry.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions why a negative sign is treated as a group or atom in the context of asymmetric carbon, suggesting that if negative charges are treated as groups, positive charges should be as well.
  • Another participant emphasizes the importance of understanding the level of the class to tailor the explanation appropriately.
  • There is a discussion about the presence of electrons associated with charges, with one participant asserting that negative charges do not correspond to an atom carrying the charge.
  • Concerns are raised about the validity of examples used to illustrate the presence of electrons, with one participant questioning the stability of nitrogen in certain bonding scenarios.
  • Participants mention the significance of molecular geometry in determining the characteristics of carbon atoms, including whether they are asymmetric.
  • One participant introduces the concept of lone pairs and orbitals, indicating a shift in focus from charges to molecular structure.

Areas of Agreement / Disagreement

Participants express differing views on the treatment of charges as groups or atoms, with no consensus reached on the implications for carbon asymmetry. The discussion remains unresolved regarding the validity of examples and the relationship between charge and molecular structure.

Contextual Notes

Limitations include potential misunderstandings of molecular stability and the implications of charge on molecular geometry. The discussion does not resolve the criteria for determining asymmetry in carbon atoms.

gracy
Messages
2,486
Reaction score
83
chiral.png

My teacher says in picture (1) carbon atom is Asymmetric carbon atom. I don't know why. I know asymmetric carbon atom are those carbon atoms which are bonded with four different groups/atoms by single bonds. But why would we treat a negative sign as a group or atom?
And I also want to ask for whatever reason we are treating negative sign as a different group we must treat + sign in a same way. Hence, carbon atom in (2) should also be asymmetrical. Right?
 
Chemistry news on Phys.org
Hi Gracy,
It would help if you would let us know what level class this is for. The explanation level should greatly depend on that.
 
Hint: difference in charges means difference in the number of electrons present. They have to "be somewhere".
 
Borek said:
They have to "be somewhere".
You mean negative charge isn't present there alone there must be an atom carrying that negative charge?
 
No. There is no atom carrying the charge.

The electron ha to be somewhere. For example in a water molecule, in an ammonia molecule, there are electrons that are not accompanied by an atom (it happens that these molecules don't carry a charge, but the idea is exactly the same).

Where do these electrons reside?
 
Are these examples you made up or your teacher made up? I don't think these represent any actual molecules that would exist (for example, the nitrogen with only a single chemical bond would be very unstable).

In general, however, it may be useful to consider the geometry of the carbon (i.e. is it trigonal planal, trigonal pyrimidal, tetrahedral, bent, linear, etc).
 
Ygggdrasil said:
Are these examples you made up or your teacher made up?
My teacher.
 
Borek said:
The electron ha to be somewhere. For example in a water molecule, in an ammonia molecule,
I think there are partial charges in water and ammonia molecules.
 
gracy said:
I think there are partial charges in water and ammonia molecules.

We are not talking about dipoles here.

Have you ever heard about a lone pair? An orbital?
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
3K
Replies
2
Views
2K
Replies
1
Views
926
  • · Replies 8 ·
Replies
8
Views
4K
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 2 ·
Replies
2
Views
7K
  • · Replies 2 ·
Replies
2
Views
2K