Photosystem 2 is a continuation of Photosystem 1, but bizarrely it was discovered first. The first step of Photosystem 2 is the sunlight (chemical energy) hitting the P680 in the thylakoid membrane and handing off all of that nice energy to an electron cell that was created by a water molecule, which then gets absorbed by chlorophyll. Because Mother Nature obeys the laws of Thermodynamics, the oxygen and hydrogen molecules left behind by the water molecule are either used or expelled by the organism
Not to worry Jonathon, I'll give you a quick crash course in photosynthesis
First of all, photosynthesis is the conversion of Chemical energy (sunlight absorbed by the plants leaves) into glucose by using chloroplast and chlorophyll to mix the chemical energy with Co2 and water
The specifics of the process of photosynthesis are confusing, so listen well! There are 2 light dependent reactions, Photosystem 1 and 2, while there is also a light independent reaction known as the Calvin cycle
This reaction is also why many plants are autotrophs, a self sustaining organism. They simply have the chlorophyll needed to create glucose.
Now that the newly charged electron is ready to go on its own, it travels down the ETC while losing its charge slowly. These hydrogen ions are then being driven into the thylakoid. In summary, the sunlight hits the P680 starting this process, the water molecule is split and one of it's thirds absorbs the energy and travels into the ETC. Meanwhile oxygen is expelled from the plant. At the end of the photosystem the electron loses it charge.
There is also a light independent cycle called the Calvin Cycle. In this cycle there are 4 parts, fixation, reduction, and regeneration. In this cycle, carbon is treated to become rubisco, which then becomes RuBP.
Photosystem 1 is a little more complicated because it backtracks quite a bit. In this photosystem we now deal with P700 getting hit by sunlight. The electron is still charged and absorbed by chlorophyll though. The Electron follows the same path down the ETC but now converts NADP+ into NADPH. Remember the hydrogen ions that got ripped from the water molecule? We are gonna put those to work by pushing them into the ATP synthase gate so they may arrive at the stroma. This converts the ADP into ATP using the hydrogen.