Question

What is the hybridization of orbitals when there is more than one acceptable Lewis structure?

Answer 1

Hybridization is defined by sigma bonds and lone pairs and is not affected by resonance, as pi bonds are delocalized and do not influence hybridization. The geometry of the electron density around atoms, not resonance structures, determines the correct hybridization in molecules like benzene.

Step-by-step explanation:

The hybridization of orbitals in a molecule with multiple Lewis structures, also known as resonance contributors, is determined based on the geometry of the electron density around the atoms. In resonance, while the π bonds can be visualized in different positions across the structures, the hybridization is defined by the sigma (σ) bonds, lone pairs of electrons, and any single unpaired electrons. For instance, in the benzene molecule's resonance forms, all carbon atoms are bonded to three other atoms without lone pairs, indicating that the hybridization remains sp². This is because hybridization involves only the sigma bonds and lone pairs associated with hybrid orbitals and not the delocalized pi bonds or resonance.

Answer 2

The hybridization of orbitals in a molecule with multiple acceptable Lewis structures depends on the resonance forms and involves a combination of hybrid orbitals.

Explanation

When a molecule has multiple valid Lewis structures, it indicates resonance, where electrons can delocalize across different arrangements of bonds. This phenomenon necessitates understanding the concept of hybridization.

Hybridization is a model used to describe the mixing of atomic orbitals to form new hybrid orbitals, providing a more accurate representation of the molecule's geometry and bonding. In cases of multiple valid structures, the actual structure is a blend, known as a resonance hybrid, of all contributing resonance structures.

For instance, take the nitrate ion
`(\(NO_3^-\))` with two valid Lewis structures due to the delocalization of the π electrons. Here, nitrogen's hybridization involves three
`\(sp^2\)` hybrid orbitals, forming three equivalent sigma bonds with oxygen atoms, and one unhybridized p orbital that accommodates the delocalized π bond.

The resulting molecular geometry is influenced by this hybridization, leading to a trigonal planar shape in the case of the nitrate ion. Therefore, in molecules with multiple valid Lewis structures, the hybridization involves a combination of hybrid orbitals to reflect the delocalization of electrons observed in resonance.