London Dispersion Force

[Bailey Giovanoli 1L]

When talking about London Dispersion force strength, in what trend does it increase? Does anyone know if there is a trend?

[Hannah Biju 1E]

There isn't really a trend but a bigger molecule will have greater London forces and if two molecules interacting are rod-shaped rather than spherically shaped, they will have greater London forces as well.

[Ayesha Aslam-Mir 3C]

What Hannah said-- the larger the surface area between two molecules, the greater opportunities to induce dipoles and have LDF interactions. This makes more sense for linear molecules. If you put two pencils together, they would touch at a greater surface area that if you put two ping pong balls together.

[Stephen Min 1I]

As the molecule gets larger, the London dispersion forces increase due to the existence of more electrons which lead to larger dipoles.

[Tatyana Bonnet 2H]

London dispersion forces are also greater as the size of the atoms/molecules get bigger. The bigger atoms have higher polarizability, will become distorted more easily and create stronger London dispersion forces. This explains the difference in boiling points as well.