A-Level CAIE Chemistry AS 3.4.2—Sigma and pi bonds Question Bank

• Describe covalent bonds by orbital overlap.

- Sigma bonds: direct overlap between bonding atoms

- Pi bonds: sideways overlap of adjacent p orbitals above and below the sigma bond

- Apply to H2, C2H6, C2H4, HCN and N2; use sp, sp2 and sp3 hybridisation