"Most favorable" Diagram

[Ghadir Seder 1G]

If on the test it asks me to draw the lewis structure that is "most favorable," how do I know which one is? And if it asks for resonance, are we supposed to draw all the different lewis structures? Or is there a way to represent resonance without drawing all the structures?

[PranaviKolla2B]

I think for resonance structures we draw all the different possible structures.

[Naji Sarsam 1F]

When the question asks to draw the "most favorable" lewis structure, it generally means just the correct one if it doesn't have resonance. However, in some cases, a molecule can have resonance where one structure is preferred over another. This has to do with the formal charge. With some molecules, one resonant structure has all the atoms with 0 formal charge--which is ideal. However, the second resonant structure will still be correct, but one atom may have a formal charge of +1 while another may have a formal charge of -1 to balance it out. In this latter case, the structure is still possible but not "most favorable"

And yes, when it asks to draw the resonance of a molecule, you have to draw all the structures.

[Kaylee Sepulveda 4G]

When referring to "most favorable", you want as many formal charges to = 0 as possible. Also, for instance, if you're drawing an ion with a net charge that is, for example, -1, your formal charges should add up to the net charge of the ion. Formal charges of 0 would indicate a more stable, or "favorable" structure.

And for your second question, when a question asks for resonance structures you'd typically draw all of the different lewis dot structures since it's kinda difficult to draw delocalized electrons.

[LeAirraBullingor2k]

The most favorable lewis structures will be the ones with the least formal charge or formal charges that add up to zero. I'm not sure if we would be asked to draw all of them but you can draw a resonance hybrid to show the different arrangements of electrons.