SME
Physical Chemistry II: Quantum & Spectroscopy · Problem type
σ, σ*, π or π*?
Use this for “Two 2p orbitals lie side by side, parallel, with opposite phases facing. What kind of MO do they make?”
Sort
Which molecular orbital do the two atomic orbitals make?
Tap a card, then tap its group.
Overlap along the bond axis makes σ; side-by-side overlap makes π. Matching phases between the nuclei bond; opposite phases put a node there and antibond (*).
Assumptions
•
The bond axis is z. An s orbital and a 2pz orbital point along it; 2pₓ and 2pᵧ stand side by side across it.
•
In phase means the lobes that meet have the same sign, so the waves add between the nuclei; out of phase, they cancel and leave a node there.
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.