Reading Claydens organic chemistry, in chapter 5 it states that Br-Br makes a good electrophile while the C-C in ethane doesnt because the energy difference between bromines bonding and anti bonding orbital is small and that of the C-C bond isnt. Is there a good way to deduce when a bond and anti-bond orbital energy difference for a molecule will be small? Why is it the case for bromine but not ethane?
