Gon
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Gon (an element that has no atomic symbol and has the atomic number of 0) is a gas element that is invisible, but its actually there. all ElementWiki elements are radioactive, the most stable isotope of Gon is "-∞ " which has a half-life of 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 yoctoseconds