Unit 3: Properties of Substances and Mixtures

Weak attractions between temporary (instantaneous) dipoles and the dipoles they induce in neighboring particles; they arise from momentary uneven electron distributions.

All atoms and molecules, polar or nonpolar; they are the only IMF acting between nonpolar molecules and noble gas atoms.

Polarizability is how easily an electron cloud is distorted; larger atoms/molecules with more electrons are more polarizable, so dispersion forces generally grow with molar mass.

I₂ has many more electrons and a larger, more polarizable electron cloud, so its London dispersion forces are much stronger.

Linear n-pentane has more surface contact between molecules than compact, spherical neopentane, giving stronger dispersion forces.

Attractions between the partial positive end of one polar molecule and the partial negative end of another; they act in addition to dispersion forces.