London Dispersion Forces (Leaving Cert Chemistry): Flashcards

Weak attractive forces between molecules from temporary dipoles

London dispersion forces

Uneven electron distribution/movement

One end δ-, other end δ+ due to electron movement

Temporary dipole causing induced dipoles in nearby molecules

Larger molecules = stronger forces

Stronger London forces = higher boiling points (more energy to overcome)

How easily electron cloud can be distorted

Higher polarisability = stronger forces

$O_2$ higher: more electrons, stronger forces

Increases down group: $F_2$ < $Cl_2$ < $Br_2$ < $I_2$

All atoms and molecules

Instantaneous/very short time