Hi, i am new here. Thought it would be good to sign up as i have just started hitting the books in preparation for my AS Level exams. So this is my first question. I think i may have done this question correctly, but i was just seeing what other people think as i am not 100% sure about it. Question: A nucleus of the radioactive isotope of bismuth Bi (213) and (83) emits a beta particle, then an alpha particle, then another beta particle before it becomes stable. a) Show that the stable nucleus formed is a Bismuth isotope My Attempt at it Bi (213) (83) → Bi (213) (84) I have added one to the proton number, because in beta decay, a neutron turns into a proton, so the nucleon number remains the same, but the proton number goes up by 1. Then for Alpha, it becomes Bi (209) (82). I have taken 4 from the nucleon number and 2 from the proton number because an alpha particle consists of 2 protons and 2 neutrons. Then after the second beta decay i ended up with Bi (209) (83). Is this correct? Thanks for your help.