Which of these is the correct equation for the dissociation of water?

h2o + h2o+< ==> h2o + oh–
h2o + h2o < ==> h3o+ + oh–
h2o < ==> h+ + oh–
h+< ==> h2o + h2o+
h2o + oh–< ==> h2o+

H₂O + H₂O <==> H₃O⁺ + OH⁻   (option 2)

Explanation:

The equation can be resumed as this:

2H₂O ⇄  H₃O⁺ + OH⁻      Kw

Water can be an acid and a base because it is able to lose or win protons, and because it has also the ability to catch hydroxides or lose them. This compound are called amphoteric.

As it is an equilibrium, we talk about Kw, constant for water equilibrium, which values  1×10⁻14, where ¨[H₃O⁺] = [OH⁻]

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.