Here's why:
* Heat of Vaporization: This is the amount of energy required to change a substance from a liquid to a gas at its boiling point.
* Intermolecular Forces: The strength of intermolecular forces between molecules determines the amount of energy needed to break them apart during vaporization. Stronger intermolecular forces lead to higher heats of vaporization.
* London Dispersion Forces: The primary intermolecular force in these diatomic molecules is London dispersion forces. These forces increase with increasing molecular size and polarizability.
Iodine (I2) is the largest molecule in the list, making it the most polarizable. This means it has the strongest London dispersion forces, leading to the highest heat of vaporization.
In summary:
* I2 > Br2 > Cl2 > F2 > O2 (Increasing heat of vaporization)
