Which statement about an atom is true ? 1. all the elements have only one nucleon (mass) number.
2. the nucleon (mass )number can be less than the proton (atomic) number.
3. the nucleon (mass) number can equal the proton (atomic) number.
4. the number of neutrons never equals the number of electrons.

a) the particles of the chair are strongly held together.

answer carbon and three oxygen atoms;

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.