What colour is observed when sodium is burned? Describe how copper (ii) sulfate can be prepared starting with Copper hydroxide and sulfuric acid Describe the crystallization process as applied in salt preparation Explain how molecular mass affect the rate of diffusion

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.

the answers are

c and c