First it would be impossible to get all elements in the liquid form. Theres no such thing as liquid hydrogen or any of the noble gases(I think) it goes below absolute zero. Even if you theoretically could, you would get water formed first which when cooled would react with the alkali and alkali earth metals and the non-metals forming acids and bases. the bases would produce hydrogen which would ignite. The acids and bases would react (and probably eat through the reaction container first) forming salts. the ions would react with the transition metals forming even more ions leaving unreactive metals such as gold and platinum with the noble gases, some CO2 water vapor and solution of ions, and a very hot beaker. That's what I think would happen.