The general mass balance equation is: in - out + generation - consumption = accumulation if the balanced quantity is a non-reactive species (neither a product or reactant), which terms should be set to zero? in out generation consumption accumulation

Generation and consumption should be set to zero.

Explanation:

In the case where the species are non-reactive, the Generation and Consumption should be set to zero.

The Generation term becomes different from zero when there is a reaction that changes the mass balance and this change didn't come from the inflow of mass.

The Consumption term also refers to a reaction where reactants are being consumed in a chemical reaction, differentiating it from the exit flow.

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.