posted by Sue L on .
What are the atomic number and the atomic mass of the
element formed when 84
218Po emits a beta particle? What
are they if the polonium emits an alpha particle?
84 218Po: 84 signifies the number of protons; 218 is the atomic mass (#protons + #neutrons)
When a beta particle is emitted, one neutron gets changed to a proton, so if 84 218 Po emits a beta particle, the number of protons will go up by one (atomic number = 85), and the atomic mass will stay the same.
When the polonium emits an alpha particle, it emits 2 protons and 2 neutrons: 82 is the atomic number, and 216 is the atomic mass
Actually, if an Alpha particle is emitted, and the atom loses two protons AND two neutrons, the mass would lower by four; while atomic number counts only protons, mass counts neutrons as well as protons. Therefor, while the number would be 82, the mass would fall to 214.