not really possible – some are gases, some are liquid (Mercury) and some are only found in compounds. Some elements have really explosive properties when mixed together; e.g. adding pure lithium or pure magnesium to water
Well it wouldn’t perhaps be the best idea as we’d all die. 🙂 We’d be mixed in with all the really toxic chemicals and life would cease to exist. Not even in the Big Bang were all the elements mixed. They happened to form through interactions with others over time.
The answer is, it would depend very much on the order you mixed them in, and also the temperature and pressure of the reaction. But many of the elements are very unreactive, so those ones (the noble gasses, Argon etc) really would not do much what ever you did to them!