connects to carbon through a single bond.

connects to carbon through a single bond. The orbitals in the molecule may be atomic, hybridized, or a combination of both. Label each orbital and type of bond. Show the bonds formed by drawing the relevant orbitals overlapping. Remember to include the orbitals for the lone pairs on oxygen.
In formaldehyde (H2CO), carbon is the central atom and is double bonded to oxygen. Each hydrogen atom connects to carbon through a single bond. The orbitals in the molecule may be atomic, hybridized, or a combination of both. Label each orbital and type of bond. Show the bonds formed by drawing the relevant orbitals overlapping. Remember to include the orbitals for the lone pairs on oxygen.

The Correct Answer and Explanation is:

In formaldehyde (H₂CO), the bonding and orbital interactions involve both hybridized and unhybridized atomic orbitals.

Structure and Orbital Overview:

Formaldehyde has a trigonal planar geometry around the central carbon atom. This suggests that carbon is sp² hybridized. Here’s how the bonding occurs:

• Carbon’s orbital hybridization:
  Carbon uses three sp² hybrid orbitals to form sigma (σ) bonds. These include:
  • One σ bond with a hydrogen atom (1s orbital of H overlaps with one sp² orbital of C)
  • A second σ bond with the second hydrogen atom (another 1s of H overlaps with a different sp² of C)
  • A third σ bond with oxygen (overlap of an sp² orbital of C with an sp² orbital of O)
• The remaining unhybridized p orbital on carbon overlaps with an unhybridized p orbital on oxygen to form a π bond, completing the C=O double bond.
• Oxygen’s orbitals:
  • Oxygen is sp² hybridized as well.
  • One of oxygen’s sp² orbitals overlaps with carbon’s sp² orbital to form a σ bond.
  • The other two sp² orbitals on oxygen hold two lone pairs of electrons.
  • The unhybridized p orbital on oxygen participates in the π bond with carbon.

Summary of Bonds:

• C–H Bonds: σ bonds formed by overlap of H (1s) with C (sp²).
• C=O Double Bond:
  • One σ bond from C (sp²) and O (sp²).
  • One π bond from side-by-side overlap of unhybridized p orbitals (one from C, one from O).
• Lone pairs on oxygen: occupy two sp² hybrid orbitals.

Diagram (Text Description):

mathematicaCopyEdit       H      H
        \    /
         C == O
        /     ..
     (sp²)  (sp² with lone pairs)

Each bond type and orbital overlap shows how formaldehyde maintains its planar geometry and bonding characteristics. The double bond between carbon and oxygen is stronger due to the π bond in addition to the σ bond.