Order C-I, C-Br, C-Cl, & C-F Bonds by Length

In summary, the bonds should be arranged in order of increasing bond length as follows: C-F, C-Cl, C-Br, C-I. This is based on the concept of electronegativity, where the most electronegative atom (fluorine) will form the shortest bond with carbon, and the least electronegative atom (iodine) will form the longest bond with carbon. This is supported by the fact that the size of the atoms follows the same pattern as electronegativity, with fluorine being the smallest and iodine being the largest. In terms of bond length, electronegativity plays a significant role in determining the strength of the bond between carbon and the halogen atom.
  • #1
henry3369
194
0
Arrange these bonds in order of increasing bond length.
C-I, C-Br, C-Cl, C-F

Is there a way to figure this out without drawing molecular orbital diagrams and determining the bond order?
 
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  • #2
its been a while since chemistry, but won't electronegativity do it , shortest being carbon with the most electronegative (flourine)?
 
  • #3
What about radii of the atoms involved? Aren't they enough to predict the outcome? These are all very similar bonds, carbon-halogen, no need for any more advanced approach when you can safely solve the problem assuming "all other factors are being equal".
 
  • #4
The radii and the electronegativity follow the same pattern in this case, one is because of the other but its amazing how much you forget in a year (i can't remember off hand why size decreases as number increases across a row, I am sure with a little thinking I'd get it)

but if either of s are right both of us are right in the context of your question and I'm pretty sure we are
 
  • #5
I am not convinced following electronegativity is a good idea. I can't think of good examples of molecules where the electronegativity is the only thing changing (or at least where all other changes are negligible) which is an important condition for such comparisons.
 
  • #6
you may be right, as I said its been a year and I can't get into my chemistry brain right now, but I'm sure electronegativity goes down with increasing radius so our answers would be the same in this context.

personally I feel just looking at the size of the atoms isn't conceptually enough, it happens to work here but the haogens sharing with carbon in the first place cause it wants those electrons bad and carbon doesn't want to give them up.
how bad the halogen wants them would be its electronegativity and changes with the halogen choosen
how much carbon wants to keep them would be its electron affinity, and is constant

sooo, how hard there pulled together should be to some degree a function of electronegativity right? like I said its been a minute and my brains in physics world atm. so any misinformation is possible and accidental
 
  • #7
Jediknight said:
I feel just looking at the size of the atoms isn't conceptually enough

In general it is not, but this is a very specific question.
 

1. How do you determine the order of C-I, C-Br, C-Cl, and C-F bonds by length?

The order of C-I, C-Br, C-Cl, and C-F bonds by length is determined by the difference in electronegativity between the two bonded atoms. The greater the difference in electronegativity, the shorter the bond length. In this case, the bond length decreases in the order C-I > C-Br > C-Cl > C-F.

2. Why does the bond length decrease as the electronegativity difference increases?

The bond length decreases as the electronegativity difference increases because the more electronegative atom will attract the shared electrons closer to itself, resulting in a shorter bond. This is due to the unequal distribution of electrons in the bond, with the more electronegative atom having a greater pull on the shared electrons.

3. How does bond length affect the strength of a bond?

The shorter the bond length, the stronger the bond. This is because the shorter distance between the bonded atoms allows for a stronger attraction between them, resulting in a stronger bond. Therefore, in the order C-I > C-Br > C-Cl > C-F, the C-F bond is the strongest and the C-I bond is the weakest.

4. Can bond length be affected by other factors besides electronegativity?

Yes, bond length can also be affected by the number of bonded atoms and the type of hybridization of the bonded atoms. For example, double bonds are usually shorter than single bonds due to the increased electron density between the bonded atoms. Additionally, as the number of bonded atoms increases, the bond length typically increases as well.

5. What is the significance of knowing the order of C-I, C-Br, C-Cl, and C-F bonds by length?

Knowing the order of C-I, C-Br, C-Cl, and C-F bonds by length can help in predicting the chemical and physical properties of molecules. For example, a molecule with a shorter C-F bond will likely have a higher boiling point than a molecule with a longer C-Cl bond, due to the stronger intermolecular forces between molecules with shorter bonds. This information is also important in understanding the reactivity of molecules, as shorter bonds are typically more reactive than longer bonds.

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