- Calculate the energy (Q) 4.18 needed to boil 50.0 g of water at room temperature (22°C) to its boiling point of 100 °C. Use the table to the right for a list of the specific heat values

the answer is barium and copper bromide

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.