Explain why CaCl2 is likely to have properties similar to those of CaBr2

Calcium chloride and calcium bromide can have similar properties since they are formed with halogen anions Cl− and Br-.

Explanation:

These elements pertain to the same group of the periodic table, and thus similar properties are expected for the salts they form

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.