POLARITY & FORCES

Polarity

The state or property of an object, system, or molecule having two opposing forces, tendencies, charges, or directions.

Electronegativity

The ability of an atom to attract shared electrons toward itself in a chemical bond.

Bond Dipole

A vector with direction and magnitude that points from the less electronegative, partially positive ($\delta^+$) atom to the more electronegative, partially negative ($\delta^-$) atom.

Bond Polarity versus Molecular Polarity

Bond polarity occurs at an individual bond level due to electronegativity differences, whereas molecular polarity describes whether the entire three-dimensional molecule has a net positive and net negative end.

Nonpolar Covalent Bond (Electronegativity Range)

A bond type with relatively equal electron sharing, occurring when $\Delta EN < 0.4$.

Polar Covalent Bond (Electronegativity Range)

A bond type characterized by unequal electron sharing, occurring when $0.4 \le \Delta EN \le 1.7$.

Ionic Bond (Electronegativity Range)

A chemical bond formed when the electronegativity difference between two atoms satisfies $\Delta EN > 1.7$.

Intramolecular Forces

Forces of attraction that hold atoms together inside a single molecule.

Intermolecular Forces

Forces of attraction or repulsion that act between separate molecules.

London Dispersion Forces

Weak, temporary electrostatic attractions present in all atoms and molecules caused by momentary fluctuations in electron distribution that form temporary dipoles.

Dipole-Dipole Forces

Intermolecular attractions occurring between the partially positive ($\delta^+$) end of one polar molecule and the partially negative ($\delta^-$) end of another polar molecule.

Hydrogen Bonding

A particularly strong type of intermolecular attraction that occurs when hydrogen is covalently bonded to nitrogen ($N$), oxygen ($O$), or fluorine ($F$).

Hydrogen Bond versus $O-H$ Covalent Bond

An $O-H$ bond is an intramolecular covalent bond inside a molecule, whereas a hydrogen bond ($H \cdots O$) is an intermolecular attraction between separate molecules.