NASA has decided to bui
Some of the scientists designing
it out of. On Earth, mercury is
as decided to build a structure on Pluto. The surface temperature of Pluto is -233
scientists designing the structure have suggested using mercury metal to make
on Earth, mercury is a liquid and it has a melting point of 40°C and a boiling
of 357 C. Would mercury be a good or bad choice for building the structure?

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.