Question

Which intermolecular force is responsible for iodine (I2) being a solid at room temperature?
Responses

dipole–dipole forces

dipole–dipole forces

dispersion forces

dispersion forces

hydrogen bonds

hydrogen bonds

ion–dipole forces

Answer 1

Dispersion forces (London forces).

I2 is nonpolar, so it has no permanent dipole or H-bonding and it isn't ionic. Its relatively large, easily polarizable electron cloud gives strong London (induced dipole–induced dipole) attractions, which are strong enough to make iodine a solid at room temperature.