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.
To determine the formal charge on the sulfur atom in the structure above, we need to follow these steps:
1. **Count the valence electrons for sulfur**: Sulfur is in group 16 of the periodic table, so it has 6 valence electrons.
2. **Count the lone pair electrons on sulfur**: In the given structure, sulfur has one lone pair of electrons, which equals 2 electrons.
3. **Count the bonding electrons around sulfur**: Sulfur is involved in one double bond with oxygen (which accounts for 4 bonding electrons) and one single bond with another oxygen (which accounts for 2 bonding electrons), totaling 6 bonding electrons. These 6 bonding electrons are shared, so sulfur effectively has 3 electrons from these bonds.
4. **Formula to calculate formal charge**:
\[
\text{Formal Charge} = \text{Valence Electrons} - (\text{Lone Pair Electrons} + \frac{1}{2} \times \text{Bonding Electrons})
\]
5. **Insert the values into the formula**:
\[
\text{Formal Charge} = 6 - (2 + \frac{1}{2} \times 6)
\]
\[
\text{Formal Charge} = 6 - (2 + 3)
\]
\[
\text{Formal Charge} = 6 - 5
\]
\[
\text{Formal Charge} = +1
\]
The formal charge on the sulfur atom in this structure is \( +1 \).
### Explanation of the Structure
- **S**: The central sulfur atom.
- **=O**: A double bond between sulfur (S) and oxygen (O), indicated by the "=" symbol.
- **-O**: A single bond between sulfur (S) and oxygen (O), indicated by the "-" symbol.
- **Lone pairs on oxygen atoms**: Each oxygen atom shows lone pairs of electrons, symbolized by the pairs of dots around the oxygen atoms.
This structure is crucial in understanding the distribution of electrons and formal charges in molecules, which influences their reactivity and properties in chemical reactions](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff7d651ae-bc59-4c10-bead-f2b72cbab32a%2Fc1434857-368f-4d46-ad93-d2bc22078c7b%2Fsv6qvbn_processed.png&w=3840&q=75)
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