Chapter 9: Molecular Geometries/Bonding Theories

These flashcards cover essential concepts from the lecture on molecular geometries and bonding theories.

Valence-Shell Electron-Pair Repulsion Theory (VSEPR)

The arrangement of electron domains that minimizes repulsions among them.

Electron Domain Geometry

The arrangement of electron domains around the central atom based on the number of domains.

Molecular Geometry

The shape defined by the positions of only the atoms in the molecule, not the nonbonding pairs.

Lone Pair

A nonbonding pair of electrons that also counts as one electron domain.

Tetrahedral Geometry

Occurs when all electron pairs around the central atom are bonding pairs.

Trigonal Planar Geometry

Occurs when there are three bonding pairs of electrons around the central atom.

Bond Polarity

How equally electrons in a bond are shared.

Dipole Moment

A measure of charge separation in a molecule.

Hybrid Orbitals

Orbitals formed by mixing atomic orbitals to accommodate bonding.

Sigma Bond

A bond characterized by head-to-head overlap of atomic orbitals.

Pi Bond

A bond characterized by side-to-side overlap of atomic orbitals.

Valence-Shell Electron-Pair Repulsion Theory (VSEPR)

The arrangement of electron domains that minimizes repulsions among them.

Electron Domain Geometry

The arrangement of electron domains around the central atom based on the number of domains.

Molecular Geometry

The shape defined by the positions of only the atoms in the molecule, not the nonbonding pairs.

Lone Pair

A nonbonding pair of electrons that also counts as one electron domain.

Tetrahedral Geometry

Occurs when all electron pairs around the central atom are bonding pairs (4 electron domains, 0 lone pairs).

Trigonal Planar Geometry

Occurs when there are three bonding pairs of electrons around the central atom (3 electron domains, 0 lone pairs).

Bond Polarity

How equally electrons in a bond are shared.

Dipole Moment

A measure of charge separation in a molecule.

Hybrid Orbitals

Orbitals formed by mixing atomic orbitals to accommodate bonding.

Sigma Bond

A bond characterized by head-to-head overlap of atomic orbitals.

Pi Bond

A bond characterized by side-to-side overlap of atomic orbitals.

Electron Domain

A region in a molecule where electrons are concentrated, including lone pairs, single bonds, double bonds, and triple bonds.

Difference between Electron Domain Geometry and Molecular Geometry

Electron domain geometry considers all electron domains (bonding and nonbonding pairs), while molecular geometry considers only the positions of the atoms.

Linear Molecular Geometry

Occurs when there are 2 electron domains around the central atom and 0 lone pairs, resulting in a bond angle of 180^{\circ}.

Trigonal Pyramidal Molecular Geometry

Occurs with 4 electron domains around the central atom, with 3 bonding pairs and 1 lone pair (e.g., NH_3).

Bent Molecular Geometry (e.g., H_2O)

Occurs with 4 electron domains around the central atom, with 2 bonding pairs and 2 lone pairs.

sp Hybridization

The mixing of one s atomic orbital and one p atomic orbital to form two equivalent sp hybrid orbitals, oriented 180^{\circ} apart, responsible for linear geometry.

Molecular Polarity

A molecule is polar if it contains polar bonds and its molecular geometry is asymmetric, leading to a net dipole moment.