A reaction at -4.0 ° C evolves 256. Mmol of boron trifluoride gas. Calculate the volume of boron trifluoride gas that is collected. You can assume the pressure in the room is exactly 1 atm. Be sure your answer has the correct number of significant digits.

answer///carbon;

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.