To assign formal charges to the atoms in the carbon monoxide ([tex]\(CO\)[/tex]) molecule, let's follow a step-by-step method:
1. Write down the Lewis structure:
- The given structure for [tex]\(CO\)[/tex] is:
[tex]\[
: C \equiv O :
\][/tex]
In this structure, there is a triple bond between carbon (C) and oxygen (O), and each atom has one lone pair of electrons.
2. Determine the number of valence electrons for each atom:
- Carbon (C) has 4 valence electrons.
- Oxygen (O) has 6 valence electrons.
3. Assign electrons to each atom:
- Count the bonding electrons and non-bonding (lone pair) electrons around each atom.
- In the triple bond, there are 3 pairs (6 electrons) shared between C and O.
- Each atom also has one lone pair (2 electrons).
4. Apply the formal charge formula:
Formal charge is calculated using the formula:
[tex]\[
\text{Formal charge} = \text{(Valence electrons}) - (\text{Non-bonding electrons}) - \frac{(\text{Bonding electrons})}{2}
\][/tex]
- For Carbon (C):
[tex]\[
\text{Valence electrons} = 4
\][/tex]
[tex]\[
\text{Non-bonding electrons} = 2 \quad (\text{one lone pair})
\][/tex]
[tex]\[
\text{Bonding electrons} = 6 \quad (\text{triple bond})
\][/tex]
Using the formal charge formula:
[tex]\[
\text{Formal charge (C)} = 4 - 2 - \frac{6}{2} = 4 - 2 - 3 = -1
\][/tex]
So, the formal charge on carbon is [tex]\(-1\)[/tex].
- For Oxygen (O):
[tex]\[
\text{Valence electrons} = 6
\][/tex]
[tex]\[
\text{Non-bonding electrons} = 2 \quad (\text{one lone pair})
\][/tex]
[tex]\[
\text{Bonding electrons} = 6 \quad (\text{triple bond})
\][/tex]
Using the formal charge formula:
[tex]\[
\text{Formal charge (O)} = 6 - 2 - \frac{6}{2} = 6 - 2 - 3 = 1
\][/tex]
So, the formal charge on oxygen is [tex]\(+1\)[/tex].
Based on these calculations, we can summarize the formal charges of each atom in the molecule as follows:
\begin{tabular}{|c|c|}
\hline
atom & formal charge \\
\hline
C & [tex]\(-1\)[/tex] \\
\hline
O & [tex]\(+1\)[/tex] \\
\hline
\end{tabular}
