Valence Bond Theory Flashcards

Flashcards covering the fundamental concepts of Valence Bond Theory, including orbital overlap, bond types, and molecular energy configurations.

Scientific Theory

A strongly supported explanation for observed natural laws or large bodies of experimental data that must explain data and predict behavior.

VSEPR Theory

A theory that predicts three-dimensional molecular shapes consistent with experimental data but does not provide an explanation of chemical bonding.

Valence Bond Theory

A theory describing a covalent bond as the overlap of half-filled atomic orbitals that yield a pair of electrons shared between two bonded atoms.

Orbital Overlap

Occurs when a portion of one atomic orbital and a portion of a second orbital occupy the same region of space.

Covalent Bond

A force that physically links two atoms through the mutual attraction between a shared negatively charged electron pair and the atoms' positively charged nuclei.

Bond Distance

The optimum distance between two bonded nuclei at which the energy reaches its lowest, most stable value and attractive and repulsive forces combine for the lowest energy configuration.

$H_2$ Bond Length

The internuclear distance at the lowest energy state for a hydrogen molecule, which is exactly $74\,pm$.

$H_2$ Lowest Energy Value

The stable energy value at the optimum bond distance for two hydrogen atoms, recorded as $-7.24 \times 10^{-19}\,J$.

Sigma ($\sigma$) bond

A covalent bond where electron density is concentrated along the internuclear axis, formed by the overlap of two s orbitals, an s and p orbital, or end-to-end p orbitals.

Pi ($\pi$) bond

A type of covalent bond resulting from the side-by-side overlap of two p orbitals, where overlap regions lie on opposite sides of the internuclear axis.

Node

A plane with no probability of finding an electron, located along the internuclear axis in a $\pi$ bond.

Single Bond

In valence bond theory, this is described as a single $\sigma$ bond.

Double Bond

A multiple bond consisting of one $\sigma$ bond and one $\pi$ bond.

Triple Bond

A multiple bond consisting of one $\sigma$ bond and two $\pi$ bonds.