(a(i))[1]
State the two nuclides that have an equal number of protons.
(a(ii))[1]
State the two nuclides that have an equal number of nucleons.
(a(iii))[1]
State which of the four nuclides has the greatest number of electrons orbiting in a neutral atom.
(b)[3]
Calculate the mass of thorium-234 left after $72\,\text{days}$.