Final answer:
Based on the expected intermolecular forces,The halogen with the lowest boiling point is fluorine (F2).The trends in observed melting and boiling points for the halogens demonstrate this effect, as seen in Table 10.1.
Step-by-step explanation:
Based on the expected intermolecular forces, the halogen with the lowest boiling point is fluorine (F2).
Larger and heavier atoms and molecules exhibit stronger dispersion forces than do smaller and lighter atoms and molecules. F2 is a gas at room temperature, indicating weaker attractive forces. Therefore, it has the lowest boiling point among the given halogens.
The trends in observed melting and boiling points for the halogens demonstrate this effect, as seen in Table 10.1.
To determine which halogen has the lowest boiling point, we must consider the types and strengths of intermolecular forces at play. For the halogens mentioned (I2, F2, Br2, and Cl2), the key intermolecular force is the London dispersion force. The strength of this force correlates with the size and number of electrons in the molecule, leading to an increase in boiling points with molecular size. As such, F2 (Fluorine) with the fewest electrons and the smallest molecular size has the weakest dispersion forces and consequently, the lowest boiling point of the halogens listed.