Question

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

Explanation:

Step1: Recall Sigma Bond Definition

Sigma bonds are formed by head - on (axial) overlap of atomic orbitals, resulting in electron density along the internuclear axis. Pi bonds are formed by side - on (lateral) overlap, with electron density above and below (or in front and behind) the internuclear axis.

Step2: Analyze Each Diagram

• Diagram (a): The orbitals overlap along the internuclear axis (the straight line), so this is a sigma bond.
• Diagram (b): The orbitals overlap above and below the plane (lateral overlap), which is characteristic of a pi bond, not a sigma bond.
• Diagram (c): The overlap is lateral (above and below the plane of the axis), so it is a pi bond.
• Diagram (d): The overlap is lateral (in a plane - like, side - on manner), so it is a pi bond.
• Diagram (e): The orbitals overlap along the internuclear axis (head - on), so this is a sigma bond.
• Diagram (f): The orbitals overlap along the internuclear axis (head - on), so this is a sigma bond.

Answer:

a, e, f