Final answer:
The phase change when bromine vapor turns to bromine liquid is condensation, which is an exothermic process where energy is released.
Step-by-step explanation:
When bromine vapor turns to bromine liquid, the phase change is condensation. During condensation, energy is released as the distance between the molecules decreases and intermolecular attractions are re-established. This is because condensation is an exothermic process, meaning that heat is released as the gas phase transitions to the liquid phase, which is evident as molecular attractions become more significant.