Use principle of atomic structure and/or chemical bonding to explain why the boiling point of Cl2 is lower than the boiling point of Br2. Make sure that your response refers to both substances.

Answer 1

Br2 is a heavier molecule than the Cl2 molecule. Consider how much more energy must be added to the Br2 in order to move the molecules around as well as to have enough energy to escape (boiling) from the liquid state.