Chemistry: Molecular Geometry and Bonding Theories Summary

Flashcards focused on key vocabulary related to molecular geometry and bonding theories from chemistry.

Valence-Shell Electron-Pair Repulsion (VSEPR) Model

A model that predicts molecular shape based on the repulsion between electron pairs.

Electron Domains

Directions in which electron pairs point, including lone pairs and bonds.

Linear Geometry

Occurs when there are two electron domains opposite each other, with a bond angle of 180º.

Trigonal Planar Geometry

Occurs with three electron domains forming an equilateral triangle, with bond angles of 120º.

Tetrahedral Geometry

Occurs with four electron domains, forming a pyramid shape with a bond angle of 109.5º.

Trigonal Bipyramidal Geometry

Occurs with five electron domains, consisting of three equatorial and two axial positions with bond angles of 120º and 90º.

Octahedral Geometry

Occurs with six electron domains, with all positions equivalent and bond angles of 90º.

Hybridization

The mixing of atomic orbitals to form new hybrid orbitals.

Sigma (σ) Bond

A bond formed by head-to-head overlap of orbitals, characterized by cylindrical symmetry.

Pi (π) Bond

A bond formed by sideways overlap of p orbitals, characterized by electron density above and below the internuclear axis.

Localized Electrons

Electrons that are specifically shared between two atoms.

Delocalized Electrons

Electrons that are shared by multiple atoms, often seen in resonance structures.

Bond Order

The number of chemical bonds between a pair of atoms, indicating bond strength.

Paramagnetism

The presence of unpaired electrons, leading to attraction to magnetic fields.

Diamagnetism

The condition where all electrons are spin-paired, resulting in weak repulsion from magnetic fields.

Molecular Orbital (MO) Theory

A theory that describes the behavior of electrons in molecules using molecular orbitals formed from atomic orbitals.

Resonance Structures

Different ways of drawing a molecule that can represent the same substance, reflecting delocalized electrons.

Octet Rule

The principle that atoms tend to bond until they are surrounded by eight valence electrons.

Electron-Domain Geometry

The spatial arrangement of electron pairs (bonds and lone pairs) around a central atom.

Nonbonding Pairs

Electron pairs that are not involved in bonding and occupy more space than bonding pairs, affecting bond angles.