Hello ("wait a second"). I'm sorry to tell you that the name 2-ethylpentene is incorrect (1:30-2:55) and that actually the one that you were discussing after this name was the right one (3-methylidenehexane). The longest chain supersedes a shorter unsaturated chain (this rule was published around 20 years ago). Please, be more careful when teaching nomenclature. Students (and people in general) are confused. Don't make it more confusing. Cheers
