Iodine

[Sally kim 4F]

Why is the interaction between I2 the strongest out of Br2, F2, Cl2?

[Michelle Shin 4B]

Because I2 is a bigger molecule, it has stronger London dispersion forces.

[Indy Bui 1l]

Iodine has a larger atomic radius and more electrons than the other halogens. This makes it stronger.

[William Francis 2E]

Iodine has a larger atomic radius than bromine, fluorine, and chlorine as a result of its added shells of electrons. All of iodine's electrons are just sloshing around with potential to unevenly distribute charge throughout the atom. This sloshing results in Van Der Waal's forces or London Dispersion forces between molecules.

[Nick Lewis 4F]

Isn't there a greater shielding effect because iodine has a larger atomic radius than the other molecules? Im having trouble conceptualizing this becuase I would think F2 would have a stronger interaction because fluorine is the most electronegative atom and I thought they want the electrons the most.

[lilymayek_1E]

Isn't there a greater shielding effect because iodine has a larger atomic radius than the other molecules? Im having trouble conceptualizing this becuase I would think F2 would have a stronger interaction because fluorine is the most electronegative atom and I thought they want the electrons the most.

this is explained by polarizability, or the ability of an atom's electron cloud to be strongly manipulated by another atom. larger atoms have higher polarizability (a high tendency for the cloud to easily be manipulated and pulled toward the other charge). fluorine isn't highly polarizable - its atomic radius is very small and wants to hold onto its own electrons very closely - it'd rather take an electron than share. this explains F2's gas form at room temp (loose interaction; likes to keep its own electrons close over sharing) versus I2's solid form (strong attractive force). because Iodine's electron cloud is easily distorted, the electron clouds in I2 overlap strongly and are thus more "attractive" - the more overlap in the clouds, the stronger the force.
basically, attractive forces increase as size/molar mass increases because of greater polarizability/electron cloud overlap.

[Jacob Villar 2C]

The London dispersion forces within I2 are much stronger due to its larger atomic radius.