General Chemistry: Chemical Bonding, Molecular Structure, and Intermolecular Forces

Comprehensive practice flashcards covering course requirements, chemical bonding, Lewis structures, formal charge, hybridization, VSEPR theory, intermolecular forces, properties of liquids, solids, and phase diagrams.

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Covalent Bond

A chemical bond formed when two atoms share one or more pairs of electrons.

Ionic Bond

A chemical bond formed through the transfer of electrons resulting in electrostatic attraction between oppositely charged ions.

Electronegativity

A measure of the capacity of an atom in a compound to attract shared electrons to itself.

Debye (D)

The unit of measurement used in physics and chemistry to express the electric dipole moment of molecules.

Octet Expansion

A phenomenon in elements of the third period and beyond where the central atom holds more than eight valence electrons by utilizing available $3d$ orbitals.

Formal Charge

The theoretical charge assigned to an atom in a molecule, calculated as $\text{CF} = (\text{valence } e^-) - (\text{unshared } e^-) - \frac{1}{2}(\text{shared } e^-)$.

Dative Bond

A covalent bond formed when both shared electrons originate from a single electron-rich atom into an unoccupied orbital of an electron-deficient atom.

Valence Bond Theory (VBT)

A model describing a covalent bond as the overlap of half-filled atomic orbitals, concentrating electron density between the bonded nuclei.

Sigma ($\text{σ}$) Bond

A covalent bond formed by the head-on (frontal) overlap of atomic orbitals, concentrating electron density along the internuclear axis.

Pi ($\text{π}$) Bond

A covalent bond formed by the sideways (parallel) overlap of unhybridized $p$ atomic orbitals, concentrating electron density above and below the internuclear axis.

Orbital Hybridization

The mathematical combination of pure atomic orbitals on an atom to form new, equivalent hybrid orbitals optimized for covalent bonding.

$sp^3$ Hybridization

The mixing of one $s$ orbital and three $p$ orbitals forming four hybrid orbitals directed toward the vertices of a tetrahedron with $109.5^\text{o}$ bond angles.

$sp^2$ Hybridization

The mixing of one $s$ orbital and two $p$ orbitals forming three hybrid orbitals in a trigonal planar arrangement with $120^\text{o}$ bond angles, leaving one unhybridized $p$ orbital.

$sp$ Hybridization

The mixing of one $s$ orbital and one $p$ orbital forming two linear hybrid orbitals with $180^\text{o}$ bond angles, leaving two unhybridized $p$ orbitals.

$sp^3d$ Hybridization

The mixing of one $s$, three $p$, and one $d$ orbital on a central atom, producing five hybrid orbitals in a trigonal bipyramidal geometry.

$sp^3d^2$ Hybridization

The mixing of one $s$, three $p$, and two $d$ orbitals on a central atom, producing six hybrid orbitals in an octahedral geometry.

VSEPR Theory

Valence Shell Electron Pair Repulsion theory (Gillespie-Nyholm model), which predicts molecular geometry by minimizing electrostatic repulsions between electron domains around a central atom.

Electron Domain Repulsion Hierarchy

The relative magnitude of repulsions between electron pairs, ordered as: Lone Pair–Lone Pair > Lone Pair–Bonding Pair > Bonding Pair–Bonding Pair.

Ion-Dipole Force

An attractive force between a fully charged ion and the partial charge of a polar molecule, with typical interaction energy around $15\,kJ\,mol^{-1}$.

Dipole-Dipole Force

An intermolecular attraction between the permanent opposite poles of adjacent polar molecules, with typical interaction energy ranging from $0.3\,kJ\,mol^{-1}$ to $2\,kJ\,mol^{-1}$.

London Dispersion Force

An intermolecular attraction present in all atoms and molecules arising from temporary electron density fluctuations that induce instantaneous dipoles, with typical energy around $2\,kJ\,mol^{-1}$.

Hydrogen Bond

A strong dipole-dipole attraction occurring when hydrogen is directly bound to highly electronegative atoms ($N$, $O$, or $F$), with typical interaction energy around $20\,kJ\,mol^{-1}$.

Surface Tension

The amount of energy required to stretch or increase the surface area of a liquid per unit area.

Cohesion

The intermolecular attraction between identical molecules within a substance.

Adhesion

The attraction between non-identical molecules, such as between a liquid and the container wall.

Hard Water

Water containing high concentrations of dissolved $Ca^{2+}$ and $Mg^{2+}$ salts, categorized as hard when exceeding $151\,ppm$ ($mg\,dm^{-3}$) of $CaCO_3$.

Amorphous Solid

A solid that lacks a well-defined, long-range three-dimensional periodic structure or order.

Unit Cell

The basic repeating structural unit of a crystalline solid that generates the entire crystal lattice in three dimensions.

Covalent Network Solid

A solid consisting of atoms held together throughout a continuous network by covalent bonds, resulting in high hardness and elevated melting points.

Molecular Solid

A solid composed of discrete atoms or molecules held together by weak intermolecular forces, resulting in softness and low melting points ($< 200\,^∘\text{C}$).

Metallic Solid

A solid composed of metal cations immersed in a delocalized sea of valence electrons, imparting high electrical and thermal conductivity.

Triple Point

The unique temperature and pressure condition at which solid, liquid, and gas phases coexist in dynamic equilibrium.

Critical Point

The specific temperature and pressure above which the distinction between liquid and gas phases vanishes.