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 on Central Atoms
**Question:**
What is the formal charge on the indicated central atoms in each of the following structures?
**Structures:**
1. The first structure is a phosphorus (P) atom double-bonded to two oxygen (O) atoms.
2. The second structure is a bromine (Br) atom double-bonded to three oxygen (O) atoms, and there is one oxygen atom single-bonded to it with a lone pair present.
3. The third structure is a sulfur (S) atom double-bonded to two oxygen (O) atoms.
**Table: Formal Charges Possibilities**
| | P | Br | S |
|---|----|----|----|
| A | −1 | +1 | 0 |
| B | +1 | +1 | +1 |
| C | −1 | −1 | −1 |
| D | +1 | 0 | +1 |
| E | 0 | +1 | −1 |
**Answer choices:**
- D
- E
- A
- C
- B
**Explanation of Diagrams:**
- **Structure 1 (Phosphorus):**
- Phosphorus (P) is in the center.
- It is double-bonded to two oxygen (O) atoms.
- No lone pairs on phosphorus are shown.
- **Structure 2 (Bromine):**
- Bromine (Br) is in the center.
- It is double-bonded to three oxygen (O) atoms.
- It has a single-bond with one oxygen atom with a lone pair present.
- **Structure 3 (Sulfur):**
- Sulfur (S) is in the center.
- It is double-bonded to two oxygen (O) atoms.
- No lone pairs on sulfur are shown.
To determine the correct answer, you would typically calculate the formal charge based on the Lewis structures. The formula for the formal charge (FC) is:
\[ \text{FC} = \text{Valence electrons} - (\text{Lone pair electrons} + \frac{1}{2} \times \text{Bonding electrons}) \]
Using this method, you can identify the formal charges of the indicated central atoms and match it with one of the options from the table.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F0a6c9e0c-0b6a-4785-ae3f-5e292bd65bb9%2F7dfe59ba-334b-4068-9a3e-37657f43bbe8%2Fn1vgn96_processed.jpeg&w=3840&q=75)
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