lewis structure

Moderators: Chem_Mod, Chem_Admin

Tiffanny_Carranza_2D
Posts: 64
Joined: Fri Oct 02, 2020 12:15 am

lewis structure

Postby Tiffanny_Carranza_2D » Fri Nov 06, 2020 11:13 pm

something I was confused about in lecture was when professor put a negative sign outside of the brackets of a lewis structure

[Leis Structure]-

how do we know when to put a negative or a +?

thank you.

Sabine Salvucci 2E
Posts: 87
Joined: Wed Sep 30, 2020 9:42 pm
Been upvoted: 1 time

Re: lewis structure

Postby Sabine Salvucci 2E » Fri Nov 06, 2020 11:18 pm

The negative or positive sign outside the brackets represents the charge of the molecule. For example, if you are drawing the lewis structure of NO3-, you would put a - outside the bracket. If you are drawing SO42-, you would put 2- outside of the brackets. Hope this helps!
Last edited by Sabine Salvucci 2E on Fri Nov 06, 2020 11:20 pm, edited 1 time in total.

Alex Mele 2A
Posts: 108
Joined: Wed Sep 30, 2020 9:52 pm
Been upvoted: 4 times

Re: lewis structure

Postby Alex Mele 2A » Fri Nov 06, 2020 11:18 pm

This notation shows the charge of the ion as a whole (not formal charge of each atom). You know to put + outside of the lewis structure of something with a net +1 charge, +2 for +2 charge, - for a -1 charge, and so on. You don't need to put a charge outside of brackets for a neutral atom.

tamara masri_3D
Posts: 52
Joined: Wed Sep 30, 2020 9:35 pm
Been upvoted: 1 time

Re: lewis structure

Postby tamara masri_3D » Fri Nov 06, 2020 11:20 pm

Hello! The bracket with the charge on the outside just means that the molecule has that charge. For example, a lewis structure for the ion Cl- would be [Cl]-. You know when to put it because it is given to you in the molecular formula.

Shruti Kulkarni 2I
Posts: 95
Joined: Thu Oct 08, 2020 12:16 am

Re: lewis structure

Postby Shruti Kulkarni 2I » Fri Nov 06, 2020 11:45 pm

Hi! So the charge on the outside of the brackets represents the overall charge of the atom or molecule. Usually, you can figure out the charge of the molecule based on the properties of the atoms that make it up. As Dr.Lavelle said in the lecture, you would use the formula (FC = ( S/2 + LP)) to find the charge of an atom, with FC being the formal charge of the atom, S being the shared electrons, and LP being the lone pairs. Then you would add up the different charges of each atom in the molecule to find the overall charge of the molecule.

Brianna Chen 3F
Posts: 98
Joined: Wed Sep 30, 2020 10:11 pm

Re: lewis structure

Postby Brianna Chen 3F » Sat Nov 07, 2020 12:42 am

Depending on the charge of the atom or molecule, that will determine which charge goes outside of the brackets. For example, NO3- would be [NO3]- (with the negative charge on the outside of the brackets).

Binyu You
Posts: 54
Joined: Wed Sep 30, 2020 9:37 pm

Re: lewis structure

Postby Binyu You » Sat Nov 07, 2020 1:36 am

I think the positive(+) or negative(-) sign outside the brackets usually shows the molecule's charge. If the atom is neutral, than no sign is needed.

JakeSaum_1A
Posts: 90
Joined: Wed Sep 30, 2020 9:34 pm

Re: lewis structure

Postby JakeSaum_1A » Sat Nov 07, 2020 9:52 am

If the molecule has an overall positive charge then you add a + to the outside and if it has an overall negative charge, you add a - to the outside

Liam Bertrand 3
Posts: 82
Joined: Wed Sep 30, 2020 9:53 pm

Re: lewis structure

Postby Liam Bertrand 3 » Sat Nov 07, 2020 1:08 pm

The brackets and charge on the outside of the diagram has to do with the overall charge of the molecule. However, partial positive and negative charges can be attributed to each atom in the molecule.

Colin Squire 3B
Posts: 85
Joined: Wed Sep 30, 2020 9:35 pm

Re: lewis structure

Postby Colin Squire 3B » Sat Nov 07, 2020 2:01 pm

The charge symbol on the outside of the brackets essentially shows the overall charge of the molecule. For example, for sulfite, SO3 2-, you would have your Lewis structure [SO3] and the charge, indicated by the 2-, goes on the outside of it. It'll look like this, [SO3]2-.

Sophia Spungin 2E
Posts: 94
Joined: Wed Sep 30, 2020 9:41 pm

Re: lewis structure

Postby Sophia Spungin 2E » Sat Nov 07, 2020 2:39 pm

It's dependent on whether the number of electrons in the diagram is more or less than the number of expected electrons from the elements present.

For example, if the number of electrons expected from the elements present is 26, but only 25 are present in the lewis structure, the diagram would have a +1 charge.

Jaclyn Schwartz 1I
Posts: 94
Joined: Wed Sep 30, 2020 9:45 pm

Re: lewis structure

Postby Jaclyn Schwartz 1I » Sun Nov 08, 2020 6:52 pm

The brackets help indicate that the molecule is an ion, and the charge outside the brackets is the total charge of the ions.

Madisen Brown -1C
Posts: 54
Joined: Wed Sep 30, 2020 9:49 pm

Re: lewis structure

Postby Madisen Brown -1C » Sun Nov 08, 2020 6:55 pm

The positive and negative symbols represent the charge of the molecule. Hope this helps!

Tiffanny_Carranza_2D
Posts: 64
Joined: Fri Oct 02, 2020 12:15 am

Re: lewis structure

Postby Tiffanny_Carranza_2D » Sun Nov 08, 2020 9:00 pm

Sabine Salvucci 1C wrote:The negative or positive sign outside the brackets represents the charge of the molecule. For example, if you are drawing the lewis structure of NO3-, you would put a - outside the bracket. If you are drawing SO42-, you would put 2- outside of the brackets. Hope this helps!


thank you for your help. I was confused because I thought there was math behind find the negative or positive sign.

Yeprem
Posts: 77
Joined: Wed Sep 30, 2020 9:40 pm

Re: lewis structure

Postby Yeprem » Sun Nov 08, 2020 9:19 pm

I think we are either going to be given the formula with the sign or given the number of electrons the molecule has and based on the elements' number of valence electrons we can figure out whether the number that is given to us is over, under, or equal to the number of total valence electrons for that molecule.

Claudia_Danysh_2B
Posts: 84
Joined: Wed Sep 30, 2020 9:58 pm

Re: lewis structure

Postby Claudia_Danysh_2B » Sun Nov 08, 2020 10:00 pm

Usually, you can know by identifying what the overall charge of the atom is!

Katie Le 3K
Posts: 73
Joined: Wed Sep 30, 2020 9:35 pm

Re: lewis structure

Postby Katie Le 3K » Mon Nov 09, 2020 12:13 am

The negative and positive refers to the charge. You can find it out by finding the formal charge of each element and just adding them all together.

Katie Nye 2F
Posts: 90
Joined: Wed Sep 30, 2020 9:55 pm

Re: lewis structure

Postby Katie Nye 2F » Mon Nov 09, 2020 12:14 am

The charge outside of the bracket represents the charge of the whole molecule. This can be seen in the charge placed on the molecular formula (such as NH4+) or by combining the formal charges of individual atoms.


Return to “Lewis Structures”

Who is online

Users browsing this forum: No registered users and 1 guest