Which is a characteristic of mixtures? They are chemicaly bonded together.
They can be classified as pure substances.
They have fixed ratios between their components.
They can be separated by physical processes.

They can be separated by physical processes.

Explanation: A mixture is made up of two or more substances that are not chemically combined and can be easily separated into its constituents by physical methods.

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.