Oxygen, for example, is very reactive, and if it is closest to hydrogen, it will make hydroxide. If it is nearest to carbon, it will make carbon monoxide. "That random reactive nature applies to pretty much all elements," Tuckerman says. "You could run this experiment 100 times and get 100 different combinations." Certain elements, such as the noble gases, wouldn't react with anything, so you'd be left with those and a few commonly found two- and three-atom molecules.