Do Intermolecular Forces Increase with Size?

A small molecule like methane has very weak intermolecular forces, and has a low boiling point. However, as molecular weight increases, boiling point also goes up. ... Therefore, dispersion forces increase with increasing molecular weight.

Do larger molecules have stronger intermolecular forces?

Molecular Size

Larger and heavier atoms and molecules exhibit stronger dispersion forces than smaller and lighter ones. In a larger atom or molecule, the valence electrons are, on average, farther from the nuclei than in a smaller atom or molecule. They are less tightly held and can more easily form temporary dipoles.

What increases as intermolecular forces increase?

As the intermolecular attraction increases, • The vapor pressure ( the pressure of the vapor that is in equilibrium with its liquid) decreases • The boiling point ( the temperature at which the vapor pressure becomes equal to the pressure exerted on the surface of the liquid) increases • Surface tension ( the ...