Pi Bond Orbital Overlap in Ethene

Steps:

• Ethene's C=C double bond consists of one sigma bond from sp² hybrid orbitals overlapping end-to-end and one pi bond from unhybridized p orbitals.
• The pi bond forms by sideways overlap of parallel p orbitals above and below the molecular plane.
• Identify diagrams showing p orbitals (dumbbell-shaped lobes) overlapping laterally, not head-on.
• Eliminate options with end-to-end or non-p orbital overlaps.

Why C is correct:

• C depicts sideways overlap of two p orbitals, matching the pi bond definition where electron density is concentrated above and below the bond axis.

Why the others are wrong:

• A shows end-to-end s or hybrid orbital overlap, forming a sigma bond.
• B illustrates p orbitals overlapping head-on, which forms a sigma bond.
• D shows non-parallel p orbitals or incorrect hybridization, not true pi overlap.

Final answer: C