I want to know the way, how to know which atom has greatest coefficient in a particular MO level in π-MO of a π conjugated system. I faced this problem when I was going through weak nucleophile attack in the beta C of Acrolein as they say that weak nucleophiles attack the beta carbon of acrolein because it has highest coefficient in the LUMO. But I wanna know how beta Carbon has highest coefficient in the LUMO of acrolein? Is there any method by comparing the electronegativities of the atoms? I know the process to decide this in case of normal MO but I can not get it in π-Mo of π conjugated system.