Final answer:
When the terminal phosphate bond is broken in ATP, a molecule of inorganic phosphate (P_i) is formed, and energy is released. This is an exergonic reaction.
Step-by-step explanation:
When the terminal phosphate bond is broken in ATP, a molecule of inorganic phosphate (Pi) is formed, and energy is released. The reaction can be written as ATP → ADP + Pi. This is an exergonic reaction because it releases energy.