The stronger bond is in the molecule with the more electronegative atom involved. For instance, the bonds in CCl4 are stronger than those of the CBr4 because Cl has a higher electronegativity than Br due to Cl's smaller size. Electronegative atoms hold electrons more tightly, thus increasing the strength of the bond.

The y-axis should indicate the amount of potential energy (in kJ/mol), and the x-axis should represent the bond length (in pm). Since we are looking at the bond energy required to break the bond, all the bond energies should be positive. The energies are only negative when forming the bond.

The C-C vs C-H Bond Strength The relative size of the s orbital explains also why the C-C σ bond is weaker than the C-H σ bond. And that is because the hydrogen uses a “pure” s orbital (100% s character) which is closer to the nucleus than is the sp³ orbital of carbon.

Answer and Explanation: Due to hyperconjugation, the tertiary carbon atom is more stablized when the C-Hd bond is broken. Primary and Secondary Carbons are less stabilized. Thus, the C-Hd is the weakest bond.