Chemical substance can be transmuted into another element through a nuclear reaction. This is so, because all of the atoms in a sample of an element have the same number of protons, though they may be different isotopes, with differing numbers of neutrons. As of 2012, there are 118 known elements, about 80 of which are stable – that is, they do not change by radioactive decay into other elements. Some elements can occur as more than a single chemical substance (allotropes). For instance, oxygen exists as both diatomic oxygen (O) and ozone (O). The majority of elements are classified as metals.
There's More Than One of Everything received the script, he thought it "was very interesting and really kind of daring contemporary television to pull in that story... You know, it's not easy to use that kind of stuff without seeming somehow exploitive. But I thought they did it very, very well". Many critics expressed that because of the episode, they couldn't wait for the following season to begin. IGN's Ramsey Isler rated the episode 9.2/10, while website blogger io9 listed "There's More Than One of Everything" as one of the "crucial" episodes new viewers must watch to get into the show. "The Futon Critic" listed it