Chemistry - CHEMICAL BONDING Question with Solution | TestHub
The internuclear axis is x. In the orbital phase sketches, white and shaded lobes have opposite signs; changing every sign of one atomic orbital changes addition into subtraction. Both centres lie in the xy plane. Which panel represents a nonzero – π ANTIBONDING combination with a nodal plane halfway between the nuclei?
Options:
Answer:
Solution:
A π combination needs side-on overlap above and below the x axis. In I the facing upper lobes have opposite phases, and so do the facing lower lobes: destructive overlap gives an additional internuclear node. In II the facing phases agree, giving π bonding. III has the p orbital along the internuclear axis and the orbital whose xz nodal plane contains that axis, so the overlap cancels by symmetry. IV has with : reflection through the xy plane changes only the p sign, so its overlap is zero. Only I satisfies all three requirements.
