Charge of a Molecule / Distribution of Charge

[Talia Leano 2H]

Can we use formal charge to determine the charge of a molecule (to find out if it is an ion) and to figure out distributions of charge (to determine if it is polar or non-polar covalent) ?

[SainehaMaddineni_3I]

You can use formal charge to find the charge of the ion, since if you add all the formal charges, it will give you the molecule's overall charge.

[Mackenzie Van Val 3E]

The positive and negative identifiers that Dr. Lavelle used in his lectures for charge distribution seemed to be based more off of the electronegativity of an atom than the formal charges found in Lewis structures. For example, in KCl, Cl would carry the partial negative charge because it has a high electronegativity (high ionization energy and electron affinity). K would carry the partial positive because it has low electronegativity (low electronegativity and electron affinity) and thus its electrons are being pulled more towards Cl. Therefore, I'd say it's better to use periodic trends instead of formal charge to find if a molecule is polar/non-polar.

[Tanya Nguyen 1B]

To find the charge of the molecule, you would add up all of the formal charges from atom and that should give you the ion's charge.

[Sabrina Galvan 3J]

Finding the overall charge of the molecule can be found through adding all of the formal charges of the atoms within the molecule.

[George_Yin_3I]

Yes, we have done some exercises on Sapling that require us to deduce the formal charge based on the charge on the molecule. In this case, the sum of the formal charge is equal to the charge of the molecule.