Draw the lewis structure(s) for the molecule with the chemical formula c2h3n,c2h3n, where the n is connected to only one other atom. how many double bonds are there in the correct lewis structure?
The Correct Answer and Explanation is :
To draw the Lewis structure for the molecule with the chemical formula ( \text{C}_2\text{H}_3\text{N} ) where the nitrogen (N) is connected to only one other atom, we need to follow these steps:
Step 1: Determine Total Valence Electrons
- Carbon (C) has 4 valence electrons, and there are 2 carbon atoms: ( 2 \times 4 = 8 )
- Hydrogen (H) has 1 valence electron, and there are 3 hydrogen atoms: ( 3 \times 1 = 3 )
- Nitrogen (N) has 5 valence electrons: ( 5 )
Total valence electrons = ( 8 + 3 + 5 = 16 )
Step 2: Choose a Skeletal Structure
Given that nitrogen is only connected to one other atom, we can place nitrogen at the end of the chain, connected to one of the carbons. A reasonable skeletal structure is:
H
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H–C–C–N
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HStep 3: Distribute Electrons
Start by placing single bonds between the atoms and satisfying hydrogen’s need for 2 electrons:
- Each C-H bond uses 2 electrons (3 bonds = 6 electrons).
- The C-C bond uses 2 electrons (1 bond = 2 electrons).
- The C-N bond uses 2 electrons (1 bond = 2 electrons).
This accounts for ( 6 + 2 + 2 = 10 ) electrons, leaving us with ( 16 – 10 = 6 ) electrons remaining.
Step 4: Form Double Bonds
To satisfy nitrogen’s need for 3 bonds, we can form a double bond between one of the carbon atoms and nitrogen. The nitrogen now has one bond to carbon and can share two pairs (4 electrons total) with carbon, leaving us with:
H
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H–C=C=N
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HFinal Structure
The Lewis structure shows one double bond between the first carbon and nitrogen, and one double bond between the two carbon atoms.
Summary
In this structure, there is 1 double bond (between C and N) and 1 double bond (between the two carbons).
Conclusion
The final Lewis structure for ( \text{C}_2\text{H}_3\text{N} ) has a total of 2 double bonds, and the nitrogen atom is connected to only one carbon atom, satisfying its tetravalent requirement while maintaining overall molecular stability.