To determine the correct Lewis electron dot structure for the molecule H3C-OH (methanol), we should follow a structured approach. Here are the steps to construct the Lewis structure:
1. Count the total number of valence electrons.
- Hydrogen (H) has 1 valence electron.
- Carbon (C) has 4 valence electrons.
- Oxygen (O) has 6 valence electrons.
Methanol contains:
- 4 hydrogen atoms, contributing [tex]\(4 \times 1 = 4\)[/tex] electrons.
- 1 carbon atom, contributing 4 electrons.
- 1 oxygen atom, contributing 6 electrons.
Total valence electrons = [tex]\(4 \text{ (from H)} + 4 \text{ (from C)} + 6 \text{ (from O)} = 14\)[/tex] valence electrons.
2. Draw the skeleton structure of the molecule.
- Place the carbon atom in the center as it typically forms the most bonds.
- Bond the carbon to three hydrogen atoms and one oxygen atom.
- Bond the oxygen atom to one hydrogen atom.
3. Distribute the remaining electrons to complete the octet (or duet for hydrogen) of each atom.
- Start with the atoms outside the center (hydrogens first since they only need 2 electrons).
4. Place any remaining electrons around the central atom if necessary to satisfy the octet rule.
Let's draw this step-by-step:
### Skeleton Structure:
```
H
|
H - C - O - H
|
H
```
### Assign bonding electrons (each bond has 2 electrons):
```
H (2 for each bond: C-H, C-H, C-H, C-O, O-H)
|
C - H - O - H
|
H
Total bonding electrons = 5 bonds * 2 electrons/bond = 10 electrons.
```
### Distribute remaining electrons:
- We initially had 14 valence electrons. After placing 10 electrons in bonds, we are left with [tex]\(14 - 10 = 4\)[/tex] electrons.
- These remaining 4 electrons should go on the oxygen atom to satisfy its octet:
### Final Lewis Structure:
```
H
|
H - C - O - H
|
H
..
```
- Two lone pairs of electrons (4 electrons total) are placed on the oxygen atom to complete its octet.
Given the options provided, the correct answer aligns with this complete and correct structure for methanol:
```
..
O
/ \
H C-H
|
H
|
H
```
Visually, this matches the structural option where carbon and oxygen form the central structure, with lone pairs correctly shown on oxygen.
Correct Lewis electron dot structure:
```
O
|
H-C-O-H
|
H
```
