## central atom

$FC=V-(L+\frac{S}{2})$

Nare Arakelian Dis 3E
Posts: 58
Joined: Thu Jul 11, 2019 12:16 am

### central atom

Do we want to make it so that the central atom has a formal charge of zero?

Elizabeth Johnson 1I
Posts: 53
Joined: Wed Sep 11, 2019 12:16 am

### Re: central atom

yes! If it's possible, you're going to want the charges to be on the surrounding atoms rather than the central atom. I honestly couldn't tell you exactly why it's better, but it's better to not have a localized charge.

Alfred Barrion 2H
Posts: 58
Joined: Sat Jul 20, 2019 12:16 am

### Re: central atom

You would want the formal charge on the central atom to be closer to zero because its supposed to be the least electronegative.

005162902
Posts: 92
Joined: Wed Sep 18, 2019 12:15 am

### Re: central atom

Yes! If the formal charge of the central atom is zero, the central atom is in a stable state.

selatran1h
Posts: 52
Joined: Fri Aug 30, 2019 12:16 am

### Re: central atom

yes, ideally the central atom should have a formal charge of zero to create the most stable lewis structure.

derinceltik1K
Posts: 51
Joined: Sat Aug 17, 2019 12:15 am

### Re: central atom

you would want the central atom to have the lowest possible formal charge. It is better for outside atoms to carry the charge than the central atom.

Jasmine Fendi 1D
Posts: 87
Joined: Sat Aug 24, 2019 12:15 am

### Re: central atom

yes! I think that it is better to have the charge on the most electronegative atom, such as oxygen

Angela Patel 2J
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Joined: Sat Aug 24, 2019 12:17 am

### Re: central atom

How do we know what the central atom should be?

lauraxie2e
Posts: 92
Joined: Fri Aug 09, 2019 12:17 am

### Re: central atom

yes ideally you want every atom to have a formal charge of 0

Anish Patel 4B
Posts: 59
Joined: Thu Jul 11, 2019 12:17 am

### Re: central atom

APatel_4A wrote:How do we know what the central atom should be?

The central atom is usually the least electronegative one.

AniP_2D
Posts: 77
Joined: Sat Aug 17, 2019 12:17 am

### Re: central atom

Yes, when drawing a lewis structure, the optimal structure will have a central atom with formal charge 0. It would be ideal for all of the atoms to have a formal charge of 0, but since this is not always possible your main concern should be to make the central atom have a formal charge of 0.

AronCainBayot2K
Posts: 86
Joined: Fri Aug 30, 2019 12:17 am

### Re: central atom

The central atom should be the most electronegative and while creating Lewis Structures, you want the formal charge to be as close to 0 as possible. You may need to change/add bonds such as by adding double bonds to fulfill that formal charge, it just depends on the compound given.

Astrid Lunde 1I
Posts: 88
Joined: Sat Sep 07, 2019 12:16 am

### Re: central atom

APatel_4A wrote:How do we know what the central atom should be?

It is the least electronegative atom

Astrid Lunde 1I
Posts: 88
Joined: Sat Sep 07, 2019 12:16 am

### Re: central atom

Yes, the optimal structure would be the middle atom having a 0 charge.

PGao_1B
Posts: 50
Joined: Sat Jul 20, 2019 12:15 am

### Re: central atom

Yes, we want to make it so that the central atom has a formal charge of zero, or as close to zero as it can get - that would be the ideal situation.

Abigail_Hagen2G
Posts: 90
Joined: Fri Aug 09, 2019 12:17 am

### Re: central atom

Yes, the central atom should have a zero charge

Patricia Chan 1C
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

### Re: central atom

Yes, ideally the central atom should have a formal charge of 0. This is because we want the central atom to be the least electronegative atom of the molecule.

Daniel Yu 1E
Posts: 77
Joined: Sat Aug 24, 2019 12:15 am

### Re: central atom

What do you do for exceptions? Such as in an atom consisting of N and O, which would be the central atom? O technically has the lower ionization energy than N. Does the number of desired bonds matter when considering the central atom more than the electronegativity?

Aman Sankineni 2L
Posts: 88
Joined: Fri Aug 30, 2019 12:17 am

### Re: central atom

Daniel Yu 1I wrote:What do you do for exceptions? Such as in an atom consisting of N and O, which would be the central atom? O technically has the lower ionization energy than N. Does the number of desired bonds matter when considering the central atom more than the electronegativity?

I believe the atom with the lower ionization energy still should be the central atom.

Posts: 87
Joined: Wed Sep 18, 2019 12:21 am

### Re: central atom

Yes, you always want the most formal charges to be zero in any way that is possible.

Jacob Villar 2C
Posts: 90
Joined: Sat Aug 17, 2019 12:18 am

### Re: central atom

At a formal charge of zero, the atom would be the most stable, so yes.

Elizabeth Johnson 1I
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Joined: Wed Sep 11, 2019 12:16 am

### Re: central atom

Alfred Barrion 3E wrote:You would want the formal charge on the central atom to be closer to zero because its supposed to be the least electronegative.

this confuses me bc in our discussion, our TA gave the example of PCl5, which has a -1 charge. The lewis structure has the P in the middle with a formal charge of -1, but that conflicts with the general rule of wanted the charge to be delocalized. Why?