A LITTLE LIGHTBULB MOMENT
Bonding, functional groups and nomenclature
Hybridization matches electron domains around an atom
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Count regions, not just atoms, to guess the orbital mix.
The idea behind the cue
Hybridization describes how atomic orbitals mix to make bonding directions. An atom with four electron regions is often sp3, three regions sp2, and two regions sp. Lone pairs count as electron regions, not just bonds. The number of regions helps predict shape and bond angles.
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Short & simple
Count regions, not just atoms, to guess the orbital mix.
Acronym
LTT — Lopsided Tacos Tumble.
Story
A chef lines up four stools around a table, then swaps the round table for one that lets everyone sit far apart. The atom does the same by mixing orbitals to spread electron regions.
Connect the pieces
- L (Lopsided) → Linear: Two electron regions around one atom, about 180 degrees apart, often corresponding to sp hybridization.
- T (Tacos) → Trigonal planar: Three electron regions around one atom, about 120 degrees apart, often corresponding to sp2 hybridization.
- T (Tumble) → Tetrahedral: Four electron regions around one atom, about 109.5 degrees apart, often corresponding to sp3 hybridization.
- Lopsided · Linear: Two electron regions around one atom, about 180 degrees apart, often corresponding to sp hybridization.
- Tacos · Trigonal planar: Three electron regions around one atom, about 120 degrees apart, often corresponding to sp2 hybridization.
- Tumble · Tetrahedral: Four electron regions around one atom, about 109.5 degrees apart, often corresponding to sp3 hybridization.
Know the limits
Use electron domains around a specific atom; do not apply whole-molecule hybridization as if every atom is identical.
Further reading · OpenStax Organic Chemistry ↗Check your understanding
What hybridization is most consistent with a carbon atom that has two electron regions?
A. sp2
B. sp
C. No hybridization is possible
D. sp3
Reveal explanation
sp
Two electron regions correspond to linear arrangement and sp hybridization in standard valence-bond models.