Formal Charges
Formal charges have an important role in organic chemistry since this concept helps us to know whether an atom in a molecule is neutral/bears a positive or negative charge. Even if some molecules are neutral, the atoms within that molecule need not be neutral atoms.
Polarity Of Water
In simple chemical terms, polarity refers to the separation of charges in a chemical species leading into formation of two polar ends which are positively charged end and negatively charged end. Polarity in any molecule occurs due to the differences in the electronegativities of the bonded atoms. Water, as we all know has two hydrogen atoms bonded to an oxygen atom. As oxygen is more electronegative than hydrogen thus, there exists polarity in the bonds which is why water is known as a polar solvent.
Valence Bond Theory Vbt
Valence bond theory (VBT) in simple terms explains how individual atomic orbitals with an unpaired electron each, come close to each other and overlap to form a molecular orbital giving a covalent bond. It gives a quantum mechanical approach to the formation of covalent bonds with the help of wavefunctions using attractive and repulsive energies when two atoms are brought from infinity to their internuclear distance.
![### Determining Formal Charges and Lewis Structures of \( \text{SO}_3^{2-} \)
**Objective:**
Learn to assign formal charges to elements in given structures and identify the most accurate Lewis structure for the sulfate ion, \( \text{SO}_3^{2-} \).
**Step 1: Assign Formal Charges**
Assign formal charges to the elements in the structures below.
**Note:** Count oxygen atoms starting from the left for each structure.
**Structures:**
**Structure A:**
- Central sulfur (S) atom with three oxygen atoms (O) surrounding it.
- Sulfur has one double bond and two single bonds with the oxygens.
- A bracket encloses the structure indicating a \(2-\) charge.
**Structure B:**
- Similar to structure A but with a different arrangement of bonds.
- The sulfur atom forms two double bonds and one single bond with the oxygen atoms.
- Enclosed in a bracket with a \(2-\) charge.
**Structure C:**
- Sulfur is connected to three oxygen atoms in a slightly different manner with varied bond types compared to A and B.
- All oxygens are bonded by single bonds.
- Enclosed in a bracket with a \(2-\) charge.
**Formal Charge Calculation:**
Below each structure, calculate and assign the formal charges for sulfur (S) and each oxygen (O1, O2, O3).
**Formal Charge Table:**
- A table is provided to fill in the formal charges for sulfur and the three oxygen atoms in each of the structures A, B, and C.
| **Formal Charge** | **A** | **B** | **C** |
|-------------------|-------|-------|-------|
| S | [ ] | [ ] | [ ] |
| O1 | [ ] | [ ] | [ ] |
| O2 | [ ] | [ ] | [ ] |
| O3 | [ ] | [ ] | [ ] |
**Step 2: Determine the Best Lewis Structure**
Identify which Lewis structure correctly represents \( \text{SO}_3^{2-} \) based on formal charge minimization.
**Conclusion:**
The best Lewis structure for \( \text{SO}_3^{2-} \) is Structure **B** as indicated by the highlighting of the second](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F9a2edb2f-7c78-40b5-b7fe-b2ef3d716529%2Fda745476-aafa-4a05-be2f-bb66f1702211%2F1k0mkvl_processed.png&w=3840&q=75)
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