Pyridine reacts with hydroxide by nucleophilic aromatic substitution. complete the mechanism by drawing curved arrows, the structure of the charged intermediate, and the structure of the major uncharged product. all non-bonding electrons must be shown, including those associated with charges.

what is the question here. i think you messed up.

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.