## Finding the central element on the Lewis structure

YeseniaGomez_1L
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Joined: Fri Apr 06, 2018 11:02 am
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### Finding the central element on the Lewis structure

I am still confused on how you find which element goes in the center when doing lewis structure. For example in question 3.51 the book asks for 2 lewis structures for HClO, in the solution one of the structures has O in the center and the other has Cl in the center. I don't understand how to get the central element and why in the example given they exchange between O and Cl.

Yeo Bin Yook 1K
Posts: 30
Joined: Fri Apr 06, 2018 11:05 am

### Re: Finding the central element on the Lewis structure

Usually you can follow the rule on F O N Cl (Br I). Electronegativity increases from right to left, meaning that it is less likely to be in the center of the Lewis structure. If the molecule they asked for was ONF, because out of the three elements N is the least electronegative, it would be in the center.

NabilaNizam-1K
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

### Re: Finding the central element on the Lewis structure

Does this mean if the compound is made up of group 1 or 2 elements and the FONCl elements, the metal elements will always be the central element?

YeseniaGomez_1L
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Joined: Fri Apr 06, 2018 11:02 am
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### Re: Finding the central element on the Lewis structure

Yeo Bin Yook 1K wrote:Usually you can follow the rule on F O N Cl (Br I). Electronegativity increases from right to left, meaning that it is less likely to be in the center of the Lewis structure. If the molecule they asked for was ONF, because out of the three elements N is the least electronegative, it would be in the center.

I am still confused, if electronegativity increases from right to left, why is flourine the most electronegative as stated in class? Adding on, I don't really understand what the F O N Cl rule states. Thanks for the help!

Nicole Shak 1L
Posts: 35
Joined: Wed Nov 22, 2017 3:03 am

### Re: Finding the central element on the Lewis structure

Electronegativity generally increases from left to right, not right to left. Flourine is the most electronegative, and FONCl (most to least electronegative) is just a good way to remember electronegativity. So if the molecule is NOF, N would be the center because it is the LEAST electronegative.
https://marcomileschem.files.wordpress. ... nd-jpg.jpg