The following list contains some common polyatomic ions. using the charge on these ions and the idea of valence, predict the formulas for the following.

nitrate no3 - phosphate po4³-
sulfate so4²- acetate c2h3o2 -
ammonium nh4 4 chromate cro4²-
carbonate co3²- dichromate cr2o7²-
permanganate mno4 - sulfide s²-
sodium carbonate
potassium permanganate

i believe that it is a exoplanet

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.