Inductive Effect: Why Does Charge Decrease?

  • Thread starter Karan Punjabi
  • Start date
In summary, the inductive effect is the partial shifting of electron pairs towards more electronegative atoms, creating a partial charge on the carbon atoms. As the chain increases, the effect decreases and becomes negligible after 3-4 carbons due to the weaker partial charges and the suppression of the effect by the movement of bond pairs. The positive charge on carbon atoms is not as strong as that on the chlorine atom, leading to a lesser ability to attract shared electron pairs and polarize neighboring carbon atoms. The electronegativity of carbon also plays a role, but it is not as significant when bonded to another carbon atom.
  • #1
Karan Punjabi
127
3
Guys, I just understand that what is inductive effect but I'm not getting the reason that why as chain increases the positive charges on each carbon atom after 3 or 4 bonds decreases or becomes negligible?
 
Chemistry news on Phys.org
  • #3
Dr. Courtney said:
Not sure what the question is.
Consider n-pentyl chloride on 1 carbon atom which is attached to chlorine atom there is a partial positive charge and on second carbon atom it is said that there is less positive charge and as we move further we get more less positive charge. So why?
 
  • #4
Lets name the carbons to make it easier. The carbon attached to chlorine is A, the next one B... and so on.

Now the positive charge on A is generated by highly EN chlorine. It is not a complete positive charge mind you, because the electron pairs A shares with B compensate for this charge. Now the partial shifting of the electron pair A-B (electron pairs shared by A and B) towards generates a partial negative charge on B. This charge will be smaller than that on A because it is not generated due to a highly EN atom, but by another partial positive charge (which itself is weak). From B to C, the charge decreases further and we generally neglect inductive effect after 3-4 carbons.
 
  • #5
CrazyNinja said:
Lets name the carbons to make it easier. The carbon attached to chlorine is A, the next one B... and so on.

Now the positive charge on A is generated by highly EN chlorine. It is not a complete positive charge mind you, because the electron pairs A shares with B compensate for this charge. Now the partial shifting of the electron pair A-B (electron pairs shared by A and B) towards generates a partial negative charge on B. This charge will be smaller than that on A because it is not generated due to a highly EN atom, but by another partial positive charge (which itself is weak). From B to C, the charge decreases further and we generally neglect inductive effect after 3-4 carbons.
I understood you but I was going for the fact that the partial positive charge on Carbon A is having the same capacity to attract shared pairs of electrons as chlorine atom because the partial positive charge is generated due to chlorine.
 
  • #6
Sorry for the delay in answering.

Yes you are right that chlorine generates the partial positive charge. But this charge is not as strong as chlorine because its effect is suppressed by the movement of bond pair A-B. Chlorine can attract shared pairs as it is its fundamental property (being so EN). Carbon is attracting only because it has a partial charge. This charge is not sufficient enough to polarise carbon B as much as chlorine polarises carbon A.
 
  • #7
That means there are two factors for carbon i.e its electronegativity and positive charge on it
 
  • #8
Yes. But its own EN doesent olay a role when it is bonded to another carbon. C-C bonds don't have polarity.
 

1. What is the Inductive Effect?

The Inductive Effect refers to the ability of an atom or functional group to polarize a chemical bond or a group of bonds within a molecule. This occurs due to differences in electronegativity between atoms, causing a redistribution of electron density.

2. How does the Inductive Effect influence charge?

The Inductive Effect can either increase or decrease the electron density in a molecule. When an atom or group with higher electronegativity is attached to a molecule, it can pull electron density towards itself, decreasing the charge on the adjacent atoms. On the other hand, when an atom or group with lower electronegativity is attached, it can push electron density away, increasing the charge on the adjacent atoms.

3. What factors affect the strength of the Inductive Effect?

The strength of the Inductive Effect is influenced by the distance between the polarizing atom or group and the affected atoms, as well as the difference in electronegativity between them. The closer the polarizing atom or group is to the affected atoms, and the greater the difference in electronegativity, the stronger the Inductive Effect will be.

4. How does the Inductive Effect affect the acidity/basicity of a molecule?

The Inductive Effect can influence the acidity or basicity of a molecule by altering the distribution of electron density within it. If the Inductive Effect decreases the electron density on a proton, the molecule will become more acidic as it is easier for the proton to dissociate. Conversely, if the Inductive Effect increases electron density, the molecule will become more basic as it is more likely to accept a proton.

5. Can the Inductive Effect be reversed?

Yes, the Inductive Effect can be reversed by changing the relative positions of the polarizing and affected atoms or groups. For example, if a highly electronegative atom is replaced with a less electronegative one, the direction of the Inductive Effect will be reversed. Additionally, the strength of the Inductive Effect can be reduced by increasing the distance between the polarizing and affected atoms.

Similar threads

Replies
2
Views
525
Replies
8
Views
995
Replies
1
Views
1K
Replies
3
Views
3K
Replies
6
Views
4K
Replies
7
Views
5K
Replies
2
Views
2K
Replies
1
Views
1K
Back
Top