Resonance Structures and Molecular Shapes

[Sarah Spalding 3E]

Can anyone explain the relationship existing between resonance structures and their respective molecular shapes/orientations? I'm having a difficult time connecting the two concepts.

[Gurpreet Khamba 1J]

When you find the shape of a molecule, sometimes you will end up with a shape that has several atoms connecting to the center. If the center only needs 8 e- and you have plenty of electrons then things are fine. Resonance structures come into play when these connecting atoms can be changed around. In other words, lets say you have three identical atoms connecting to a center Carbon. If only one double bond is needed to complete the Carbon's octet, then the other two atoms only have singles. However which one of the three identical atoms has the double bond? As such, you can have three structures depicting a different yet similar arrangement. In reality however, no double bond exists. In reality, all three of these identical atoms shares a single/double bond with the carbon, a sort of harmony. For molecular shapes, the only thing that matters is that three atoms are connecting to a central atom.