# Why is sulfur the central atom in the Lewis structure for SO2?

So apparently the Lewis structure of $\ce{SO_2}$ is

It was my understanding that the central atom is the one that is more electronegative. And an atom is more electronegative the closer it is to Fluorine (top-right). Oxygen is definitely closer to fluorine than sulfur is. Then, why is sulfur the central atom?

Also, one thing that has been bugging me for a while: if there are two or more atoms for the central element, how do you make the Lewis structure?

• can you give example for "two or more atoms for the central element"? Jul 16, 2015 at 7:43
• @Freddy I don't have an example, but I imagine there could be a molecule with two types of elements, and the least electronegative one happens to have two or more atoms. Or is such a thing impossible? Jul 16, 2015 at 7:54
• I don't know any such molecule. But you can check out chemwiki.ucdavis.edu/Organic_Chemistry/Fundamentals/… Jul 16, 2015 at 8:06
• @Freddy how about H2O2 (just found it in the book)? Oxygen is the central since Hydrogen can't ever be. But I got two oxygens. Apparently the structure looks like this: i.stack.imgur.com/Y39wf.png, but I don't get it: shouldn't the two hydrogens be connected to the same oxygen (because it is the central)? Jul 16, 2015 at 8:09
• Being the central atom has nothing to do with electronegativity. Sometimes the central atom is the most electronegative, sometimes it is the least electronegative. Jan 15, 2017 at 19:01