how is water formed in the electron transport chain of cellular respiration?

Question

In my textbook they say that
2H+ + 1/2 O2 = H2O
since there are electrons from both NADH and FADH2, it is in fact twice as much:
4H+ + O2= 2 H2O

my question is how does 4 electrons and 4 protons(H+) combing with O2 form 2 H2O?
does this mean that H+ becomes H(with 1 electron and 1 pronton, and no longer becomes an ion?) In otherwords why are protons necessary to form water?

where do the protons(H+) come from to form water? is from the electron transport chain or is from the solution in the mitochondrial matrix?

Answer 1

water is formed as a covalent bond between oxygen and hydrogen. Because of this, the hydrogen is no longer an ion, but is instead at the proper valence level, making it a normal hydrogen atom. The water is however, negatively charged since it has more electrons than protons.

Answer 2

C. The interest of cellular respiration is to create ATP. Water is created as a effect of oxygen accepting the electrons on the top of the electron shipping chain and the hydrogen ions transported from NADH and FADH2 combining. Water is then exhaled.