UNUMPENTIUM Muscovy? is a synthetic element of the periodic table whose symbol is Mc and its atomic number is 115. ? Initially, how many transuranic elements the scientific community assigns the corresponding Latin name according to their atomic number ( un = 100 , un = 10 , Pentium = 5 ) and then decides who to honor. In this case it went to the Muscovites. Currently four isotopes are known from ²?? Mc up to ²?? Mc. The most stable isotope of Muscovy is expected to be ²?? Mc, which contains the magic number of 184 neutrons.