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VSEPR and Bond Hybridization

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VSEPR predicts a molecule's shape from a simple idea: electron domains repel and arrange to get as far apart as possible. Count domains from the Lewis structure — each bond (single, double, or triple) is one domain, and each lone pair is one domain. The domain count sets the electron geometry; the atoms alone define the molecular shape.

UNIT 2 TOPIC 2.7 • VSEPR AND BOND HYBRIDIZATION GEOMETRY ENGINE Count electron domains first, then name geometry, shape, hybridization, and polarity. DOMAIN COUNT CED ANCHOR · from the Lewis structure Each single, double, or triple bond = ONE domain. Each lone pair = ONE domain. domains = bonds + lone pairs PARENT ELECTRON GEOMETRY 2 LINEAR 180° 3 TRIGONAL PLANAR 120° 4 TETRAHEDRAL 109.5° 5 TRIGONAL BIPYRAMIDAL 90° / 120° 6 OCTAHEDRAL 90° MOLECULAR SHAPES TO RECOGNIZE 2 domains linear 3 domains trigonal planar, bent 4 domains tetrahedral, trigonal pyramidal, bent 5 domains trigonal bipyramidal, seesaw, T-shaped, linear 6 domains octahedral, square pyramidal, square planar EXAMPLES + HYBRIDIZATION CO₂ linear sp BF₃ trigonal planar sp² CH₄ tetrahedral sp³ NH₃ trig. pyramidal sp³ H₂O bent sp³ 5 & 6 domains: shapes only — no d-orbital hybridization SIGMA / PI BONDS single = 1σ double = 1σ + 1π triple = 1σ + 2π π bonds lock rotation, so geometric (cis/trans) isomers become possible. MOLECULAR POLARITY Molecular dipole = vector sum of bond dipoles; a symmetric shape can cancel polar bonds. CO₂ → nonpolar (cancels) H₂O → polar (net dipole) AP Chemistry · Unit 2 · Compound Structure & Properties
VSEPR counts electron domains from the Lewis structure: each bond (single, double, or triple) is one domain, and each lone pair is one domain. The domains push apart to minimize repulsion, setting the electron geometry — and lone pairs then bend the visible molecular shape.
Geometry Engine · Open the sandbox →

The three traps: reading a shape off the flat written formula instead of the domain count, confusing the electron geometry (all domains) with the molecular shape (atoms only), and quoting an ideal bond angle while ignoring how lone pairs squeeze it smaller. Count domains first, then subtract lone pairs to see the shape.

The work

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Lesson
VSEPR Shapes ›

VSEPR arranges electron domains to minimize repulsion; lone pairs bend the visible shape. The lesson counts domains and separates electron geometry from molecular shape, then closes with a ten-scenario check.

Skill check · 10 scenarios
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Diagnostic
10-item topic check ›

Ten items spanning the three Topic 2.7 misconceptions: shape read from the flat formula, electron geometry confused with molecular shape, and ideal bond angles quoted without the lone-pair compression.

Not started · 10 items · ~15 min
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Targeted Practice
Drill a single misconception ›

Pick one of the failure modes you missed and drill it on its own. The round is adaptive: two correct in a row clears the misconception and moves you to the next.

Take the diagnostic to identify your misconceptions
Diagnostic first