Bond energies of C-Hal bonds
|
Bond |
Bond energy/kJ mol-1 |
|
C-Cl |
346 |
|
C-Br |
290 |
|
C-I |
228 |
This sequence of bond energies should not be surprising. Going down the group the atoms get larger in radius. As a result the shared pair of electrons (the covalent bond) which hold the two atoms together are further away from the halogen nucleus and so hold it less tightly to the carbon nucleus.