Le – 19 has an atomic mass of 19.0134 u, Le – 17 has an atomic mass of 17.4629 u, and Le – 15 has an atomic mass of 15.7384 u. Use the natural abundance and atomic mass of each isotope to determine the average atomic mass of Le .

thats a little if u want the answer just look it up on google thats what i do haha : )

where are the choice options?

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.