Barium reacts with water to produce barium hydroxide and hydrogen gas. How many moles of barium hydroxide are produced when 250.0 mL of water is consumed? (NOTE: water is in the liquid state. Assume the density of water is 1.00 g/mL) What is the total number of moles of ions from barium hydroxide produced in this reaction?

im pretty sure its b

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.