Law of Multiple Proportions - Give a simple and dumbed down explanation, or give a real-world example of it. The excessive wording, "Law of multiple proportions 0 if two or more different compounds are composed of the same elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers."

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.