VSEPR and Lewis

[Moris 1H]

How can we identify the VSEPR of a molecule from its Lewis structure?

[Amanda 1A]

first, identify the central atom and its valence electrons. Then, add an electron for each bonding atom, and add or subtract for the charge (- or +) to get the total number of electrons. Divide the total by 2 to find the total number of electron pairs and use that to identify the basic VSEPR shape.

[Ashley Martinez 1G]

When working with VSEPR models I read that it doesn't matter which resonance Lewis structure we consider, can someone explain why this is?

[Taizha 1C]

@Ashley, because single bonds and multiple bonds are treated as equivalent in the VSEPR model, it doesn't matter which of the Lewis Structures contributing to a resonance structure we consider.

[Ashley Martinez 1G]

@Ashley, because single bonds and multiple bonds are treated as equivalent in the VSEPR model, it doesn't matter which of the Lewis Structures contributing to a resonance structure we consider.

I see. Are they considered equivalent due to a rule that explicitly states this? Thanks in advance.