Different between:

Hologens and 0 element

different between Hologens and 0element

Explanation:

The reactivity of the elements decreases as you decent the group. This can be seen if we observe the reaction between halogens. Elements in the same group in this periodic table have similar chemical properties. Group 0 elements are unreactive nonmetal called the noble gases.

i think   the answer is c hope i'm right

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.