Molecular Shapes and VSEPR Theory

VSEPR Theory

Predicts molecular shape based on electron pair repulsion.

Bonding Pairs

Electron pairs involved in chemical bonds.

Non-Bonding Pairs

Lone pairs of electrons not involved in bonding.

Central Atom

Atom to which other atoms are bonded.

Electron Pair Repulsion

Negative charges repel, maximizing distance between pairs.

Tetrahedral Shape

Four electron pairs, bond angles of 109.5°.

Trigonal Pyramidal

Three bonding pairs, one lone pair, bond angles 107°.

Bent Shape

Two bonding pairs, two lone pairs, bond angles 104.5°.

Linear Shape

Two bonding pairs, bond angle of 180°.

Trigonal Planar

Three bonding pairs, bond angles of 120°.

Trigonal Bipyramidal

Five bonding pairs, bond angles of 90° and 120°.

Octahedral Shape

Six bonding pairs, bond angles of 90°.

Lone Electron Pairs

Take up more space than bonding pairs.

Expanded Octet

More than eight electrons around a central atom.

Incomplete Octet

Fewer than eight electrons around a central atom.

AX General Formula

A=central atom, X=surrounding atoms, E=lone pairs.

Bond Angles

Angles between adjacent bonds in a molecule.

Electron Groups

Total count of bonding and lone pairs.

Shape Determination

Based on arrangement of electron pairs.

Molecular Architecture

Overall shape and structure of a molecule.