2.7 VSEPR & Hybridization

01Electron domains set shape

Count electron domains (bonds count once regardless of order, plus lone pairs). Domains repel and spread apart: 2 linear, 3 trigonal planar, 4 tetrahedral, 5 trigonal bipyramidal, 6 octahedral.

Lone pairs change the molecular shape name and squeeze angles: NH₃ is trigonal pyramidal (107°), H₂O bent (104.5°).

02Notebook box

2 domains sp · 3 sp² · 4 sp³. Single bond = 1 σ; double = 1 σ + 1 π; triple = 1 σ + 2 π.

Worked example: CH₂O → 3 domains on C, trigonal planar, sp², 120°, one π bond.

Key takeaways

✦Lone pairs count as domains.
✦Hybridization from domain count.
✦Symmetric shapes can be nonpolar.

Watch outBond angle depends on domains, but the shape name depends only on atoms.

Quick check

Did it stick?

1.Shape of H₂O?

2.Hybridization of C in CO₂?

3.σ and π bonds in N₂?