Question

of the options, which one(s) represent pi bonding?
a
b
c
d
e
f

Explanation:

Step1: Recall Pi Bonding

A pi (π) bond is formed by the lateral overlap of p - orbitals (or other orbitals with a nodal plane along the internuclear axis). The electron density of a π bond is above and below (or in front of and behind) the internuclear axis. In contrast, a sigma (σ) bond has electron density along the internuclear axis (head - on overlap).

Step2: Analyze Each Diagram

• Diagram (a): The electron density is along the internuclear axis (the line connecting the two atoms). This is characteristic of a sigma (σ) bond, not a pi bond.
• Diagram (b): The orbitals are overlapping laterally, with electron density above and below the plane of the internuclear axis (the horizontal lines). This is consistent with a pi bond.
• Diagram (c): The orbitals show lateral overlap, with electron density distributed in a way that is typical of a pi bond (above and below the internuclear axis plane).
• Diagram (d): The orbitals are overlapping laterally, which is a characteristic of pi bonding (electron density is not along the internuclear axis but on either side of it).
• Diagram (e): The electron density is along the internuclear axis (head - on overlap), so this is a sigma bond.
• Diagram (f): The electron density is along the internuclear axis (head - on overlap), so this is a sigma bond.

Answer:

b, c, d