Water breaks down into what 3 things during the light reactions

The process in which water is broken down during the light dependent reactions is called photolysis.

Reaction

H₂O-->1/2O₂+2e⁻+2p⁺

Atomic oxygen is released from the water molecule and reacts with another atomic oxygen to form molecular oxygen(O₂)

The hydrogen atom has only one proton and one electron so one hydrogen atom can be written as(e⁻+p⁺) in the water molecule 2 hydrogen atoms are present so there will be 2e⁻+2p⁺

Therefore the three things that result from photolysis are:

the denominator has a very specific role.