Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

1. A Review of General Chemistry

Sigma and Pi Bonds

Organic Chemistry

1. A Review of General Chemistry

Sigma and Pi Bonds

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3:33 minutes

Problem 38(1)

Textbook Question

a. Which bond would be longer?
b. Which bond would be stronger?
1. C—Cl or C—I

Verified step by step guidance

Step 1: Understand the relationship between bond length and atomic size. Bond length increases as the size of the bonded atoms increases. Iodine (I) is larger than chlorine (Cl) because it is further down the periodic table, so the C—I bond will be longer than the C—Cl bond.

Step 2: Recall the relationship between bond strength and bond length. Shorter bonds are generally stronger because the bonded atoms are closer together, leading to greater overlap of their atomic orbitals.

Step 3: Compare the bond strengths of C—Cl and C—I. Since the C—Cl bond is shorter than the C—I bond, it will also be stronger.

Step 4: Summarize the findings: The C—I bond is longer due to the larger size of iodine, and the C—Cl bond is stronger due to its shorter bond length.

Step 5: To reinforce understanding, consider periodic trends: As you move down a group in the periodic table, atomic size increases, leading to longer and weaker bonds when those atoms form covalent bonds.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Bond Length

Bond length refers to the distance between the nuclei of two bonded atoms. Generally, bond length increases with the size of the atoms involved; larger atoms have more electron shells, resulting in longer bonds. In the case of C—Cl and C—I, the iodine atom is larger than chlorine, leading to a longer C—I bond compared to the C—Cl bond.

Bond Strength

Bond strength, or bond dissociation energy, is a measure of how much energy is required to break a bond between two atoms. Stronger bonds have higher bond dissociation energies. In the comparison of C—Cl and C—I, the C—Cl bond is generally stronger due to the effective overlap of orbitals between the smaller chlorine atom and carbon, compared to the larger iodine atom.

Electronegativity

Electronegativity is the tendency of an atom to attract electrons in a bond. It influences both bond length and strength. Chlorine is more electronegative than iodine, which contributes to the stronger C—Cl bond. The difference in electronegativity affects the bond character, with C—Cl being more polar and thus stronger than the less polar C—I bond.

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