Draw the Lewis structure for butanal, which has the condensed formula CH3(CH2)2CHO

Draw the Lewis structure for butanal, which has the condensed formula CH3(CH2)2CHO. Show all hydrogen atoms and lone pairs of electrons.

The correct answer and explanation is:

Lewis Structure of Butanal (CH₃(CH₂)₂CHO)

Butanal is an aldehyde with four carbon atoms. Its condensed structural formula is CH₃–CH₂–CH₂–CHO. Here’s how we draw its Lewis structure step-by-step:

Step-by-Step Drawing:

1. Carbon Backbone:
   • Arrange four carbon atoms in a chain:
     C1–C2–C3–C4
   • C4 is the aldehyde carbon and is double-bonded to an oxygen atom (O) and single-bonded to one hydrogen (H).
2. Add Hydrogens:
   • Each carbon needs 4 bonds. Fill the hydrogens accordingly.
3. Add Oxygen and Lone Pairs:
   • The oxygen atom in the aldehyde group forms a double bond with C4 and has two lone pairs of electrons.

Lewis Structure of Butanal:

      H   H   H   O
      |   |   |  ||
H – C – C – C – C 
      |   |   |   \
      H   H   H    H

• C1 (CH₃): 3 H atoms
• C2 & C3 (CH₂ groups): each with 2 H atoms
• C4: bonded to one H and double bonded to an oxygen (O), which has 2 lone pairs

Oxygen’s lone pairs:

    ..
 : O :
    ''

Explanation (300 Words):

Butanal is an organic compound classified as an aldehyde. Aldehydes are characterized by the presence of a carbonyl group (C=O) at the end of a carbon chain, where the carbonyl carbon is also bonded to a hydrogen atom.

The molecular formula of butanal is C₄H₈O, and its condensed structural formula is CH₃(CH₂)₂CHO. This means it has a straight chain of four carbon atoms: three are alkyl groups, and the fourth is part of the aldehyde functional group.

To draw the Lewis structure, start by placing the four carbon atoms in a linear arrangement. Add hydrogen atoms so that each carbon has four bonds, the typical valence for carbon. The terminal carbon (C4) in the aldehyde is bonded to one hydrogen and double bonded to an oxygen atom, forming the formyl group (-CHO). Oxygen typically has six valence electrons, forming two bonds and keeping two lone pairs.

Each hydrogen atom forms one single bond, satisfying the duet rule. Carbon atoms satisfy the octet rule, forming up to four bonds. This structure ensures that each atom has a full outer shell: carbon with 8 electrons and hydrogen with 2.

Finally, include the two lone pairs on the oxygen atom. These non-bonding electrons are important for the molecule’s polarity and reactivity.

This Lewis structure helps predict molecular shape, reactivity, and physical properties like boiling point and solubility. For instance, the carbonyl group contributes to the polar nature of butanal, influencing its interactions in biological and chemical systems.