Chem 211 Lesson 25: Molecular Geometry, Polarity, and Dipole Moments

These flashcards cover important concepts from molecular geometry, polarity, and bonding theories discussed in Chemistry 211.

Electronegativity (EN)

A measure of the ability of an atom to attract electrons in a bond.

Dipole Moment (μ)

A quantitative measure of the polarity of a molecule, expressed in units of debye (D).

Polar Bonds

Bonds between atoms with different electronegativities, resulting in a molecule with a charge separation.

Sigma (σ) Bonds

Covalent bonds that involve the head-on overlap of atomic orbitals, with electron density concentrated between the nuclei of the bonding atoms.

Pi (π) Bonds

Covalent bonds that involve the side-to-side overlap of atomic orbitals, with electron density located above and below the line joining the nuclei.

Diatomic Molecules

Molecules composed of two atoms, which can be either homonuclear (same atoms) or heteronuclear (different atoms). Homonuclear diatomic molecules are nonpolar, while heteronuclear ones are polar.

Molecular Geometry

The three-dimensional arrangement of atoms in a molecule, influenced by the number of electron pairs surrounding the central atom.

Tetrahedral Geometry

A molecular shape with four bonding pairs and a bond angle of approximately 109.5°.

Trigonal Bipyramidal Geometry

A molecular shape with five total electron pairs, resulting in different arrangements (e.g., seesaw, T-shaped).

Octahedral Geometry

A molecular shape with six bonding pairs surrounding a central atom, leading to bond angles of 90°.

Valence Bond Theory

A theory that explains how atomic orbitals overlap to form covalent bonds, wherein atomic orbitals hybridize to create new bonding orbitals.