The oxygen leaves as waste. Electrons are excited and leave the oxidized chlorophyll. The electrons travel down the ETS in the thylakoid membrane, losing energy as they go. Some of the lost energy is used to pump a proton into the proton gradient inside the lumen of the thylakoid. The system is noncyclic.
Electrons never return to the place from which they started.
Now I want to give you the entire process of noncyclic photophosphorylation in one animated diagram. There are some things to note as you view this picture. Secondly, the outer membrane of the chloroplast is not shown. Thirdly, the events actually happen simultaneously, not progressively as I have shown them. The animation is intended to demonstrate the steps in the process.