Formal Charge Shortcut

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Rebecca Chu 1C
Posts: 27
Joined: Fri Apr 06, 2018 11:02 am

Formal Charge Shortcut

Postby Rebecca Chu 1C » Sun May 20, 2018 10:46 pm

My TA said there was a shortcut she uses for calculating formal charge. (I have Rosie.) Does anyone know what it is? I didn't write down the shortcut.

Chris Fults 1C
Posts: 27
Joined: Wed Nov 15, 2017 3:01 am

Re: Formal Charge Shortcut

Postby Chris Fults 1C » Sun May 20, 2018 10:52 pm

Its just looking at the PTOE by seeing how many valence electrons the element has and then using # of valence electrons - number of electrons in the lewis structure. For example nitrogen has 5 valence electrons so if it had 7 electrons in the lewis structure the formal charge of nitrogen would be -2.

Sam Metzger 1C
Posts: 25
Joined: Wed Apr 04, 2018 3:00 am

Re: Formal Charge Shortcut

Postby Sam Metzger 1C » Fri Jun 01, 2018 1:34 pm

I'm not sure if there is any kind of short cut to calculating the formal charge but all group 17 atoms have a formal charge of 0 when they only have one shared bond & six lone pair electrons and all group 16 molecules have a formal charge of zero when they have two shared bonds & four lone pair electrons.

Molly Oakes 1A
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

Re: Formal Charge Shortcut

Postby Molly Oakes 1A » Sun Jun 03, 2018 10:08 pm

Instead of using the equation, I take the number of valence electrons that the atom has and subtract 1 for each lone pair electron and one for each single bond attached to that atom. Maybe this is what you are referring to.

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