[Eman7 (OP)]

I'm trying to do this through the Lewis dot structure, but if barium needs to lose two electrons and hydroxide has hydrogen with already 2 electrons and oxygen with all 8 electrons, how do thesecombine? Do you separate the oxygen and hydrogen and leave the oxygen with the 8 electrons and then give one of barium's electrons to the hydrogen and then repeat the process? I know it looks like Ba(OH)2, but when I try to do this through the lewis dot structure I don't see how this happens.

[Atomic-S]

An oxygen atom has 6 electrons and 2 vacancies. Connect one of its vacancies to the electron in hydrogen, forming OH.  Do likewise with another OH pair. Each OH pair still has one remaining vacancy. Connect each of these vacancies to the two electrons available in barium.