Vapor-pressure lowering is a colligative property of a solution, which means that it depends only upon

It depends only on the concentration of molecules in a solvent. A colligative property is one that depends only on the ratio of the number of molecules of solvent to the number of molecules of solute (i.e., the concentration). It is not affected by the size of the sample or the identity of the substance.

B"hf and f-"  is the correct answer took the test on edgenuity and got it right     

Answer : option a) 84explanation :

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.