clarification

[krish shah]

I just wanted to confirm that there will be cases where the formal charges will not equal 0 or the ionic charge, and we must do whatever we can to closely resemble that.

[Bryan Cheng 1H]

Yes, certain structures will have cases where formal charge does not equal zero: for example, in sulfate, two of the oxygen atoms have nonzero formal charges. However, the net charge of the molecule/ion must equal zero (if it's a molecule) or the ionic charge (if it's an ion). Phosphate, for example, must have formal charges that add to -3, even if this is spread across multiple atoms.

[Vivek Chotai 2C]

I'm pretty sure the formal charges have to add up to the total charge of the ion. I'm not entirely sure if there are any exceptions to that rule.

[William Huang 1K]

The sum of all the formal charges should equal the charge of the compound I believe and the most likely Lewis structure is the one where there is the least formal charge on each atom.

[Martha Avila 1I]

Hello! So when determining formal charges you must keep in mind the charge of your overall ion. Your formal charges must all add up to the overall charge and if they do not you know you have made a mistake. The formal charge can be a number other than zero for example 1- or 1+ but in a case like this there may be a push that you can execute to wipe out both of these charges and get the formal charges to both equal 0. Hope this helps.

[Aneesha_Nema_3C]

Yeah it's entirely possible for the individual atoms to have nonzero formal charges; they just have to all ad up to the overall charge of the molecule. I do think that molecules with atoms that all have formal charges of 0 are more stable though.

[Kassidy Patron 1L]

I just wanted to confirm that there will be cases where the formal charges will not equal 0 or the ionic charge, and we must do whatever we can to closely resemble that.

That is true! The total formal charge won't always equal zero. Actually, there will be multiple different ions with different charges such as 2- or 1+ we would draw structures for. This was seen in the example on Monday with the sulfate ion, SO4 2-. The newer structure we drew still had a net charge of 2-. The important thing is that the newer structure had most of the atoms with a formal charge of 0, making it more stable than the initial structure drawn.