Type the correct answer in the box. Sodium carbonate (Na2CO3) is sometimes used as a water-softening agent. Suppose that a worker prepares a 0.724 M solution of Na2CO3 and
water. The volume of the solution is 1.421 liters. What is the mass of solute in the solution?
Express your answer to three significant figures.
The mass of dissolved sodium carbonate is
grams.

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.