4.95 6th ed

[805098281]

For the first part of the question, it asks to draw the most important lewis structure, but how can one structure be more important than another when you're given the molecule CH2=CHCHO?

[Jonathan Zhao 4H]

I believe it is asking for the lewis structure with the greatest contribution to the resonance, so essentially the most stable structure.

[Tessa Lawler 1A]

You'd probably want to draw the most stable structure (a good idea generally). So, the structure in which the most atoms in the molecule have a formal charge of 0.

[Ethan Breaux 2F]

Just use formal charge formula FC = Valence - [lone pair electrons - (shared electrons/2)]