Textbook Question
Determine whether each structure is likely to be colored or not. For those that you predict to be colored, indicate the extended conjugation by marking the series of continuous sp2 hybridized atoms.
(h)
16. Conjugated Systems
Conjugation Chemistry
Problem 17
Textbook Question
The ψ2 molecular orbital for octa-1,3,5,7-tetraene is shown. Draw ψ3.
<IMAGE>
Verified step by step guidance1
Step 1: Understand the molecular orbital diagram for octa-1,3,5,7-tetraene. The ψ2 orbital shown in the image represents the second molecular orbital, where alternating phases (+ and -) are present across the conjugated π-system.
Step 2: Recall that molecular orbitals are formed by the combination of atomic p orbitals. The ψ3 orbital will have one additional node compared to ψ2, as the number of nodes increases with the molecular orbital index.
Step 3: Identify the pattern of nodes in ψ2. In ψ2, there is one node (a region where the phase changes from + to - or vice versa). For ψ3, there will be two nodes, dividing the conjugated system into three regions of alternating phases.
Step 4: Draw ψ3 by placing two nodes along the conjugated π-system. Ensure that the phases alternate (+ and -) in each region, with the nodes positioned symmetrically along the molecule.
Step 5: Verify the drawing by checking that the number of nodes corresponds to the molecular orbital index (ψ3 should have two nodes) and that the phases alternate correctly across the conjugated system.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Molecular Orbitals
Molecular orbitals (MOs) are formed by the linear combination of atomic orbitals (LCAO) when atoms bond together. They describe the probability distribution of electrons in a molecule and can be classified as bonding, antibonding, or non-bonding. Understanding MOs is crucial for predicting the electronic structure and reactivity of molecules, particularly in conjugated systems like octa-1,3,5,7-tetraene.
Recommended video:
Guided course
08:41
Review of Molecular Orbitals
Conjugation
Conjugation refers to the overlap of p-orbitals across adjacent double bonds or lone pairs, allowing for delocalization of π electrons. This delocalization stabilizes the molecule and affects its electronic properties, such as color and reactivity. In octa-1,3,5,7-tetraene, the conjugated system plays a significant role in determining the shape and energy of its molecular orbitals.
Recommended video:
Guided course
03:27Conjugated states
Phase of Molecular Orbitals
The phase of a molecular orbital indicates the sign of the wave function, which can be positive or negative. In the provided diagram, blue represents positive phases, while red represents negative phases. The interaction of these phases during the formation of molecular orbitals determines whether they are bonding or antibonding, influencing the stability and energy levels of the resulting orbitals.
Recommended video:
Guided course
08:41Review of Molecular Orbitals
5:29mWatch next
Master Definition of Conjugation with a bite sized video explanation from Johnny
Start learningRelated Videos
Related Practice