As a physics student, I understand that α particles are emitted and are the same as helium atoms without electrons. But this raises two questions to me: 1) What happens with the electrons at the atom that emits them? He now has two electrons too much. What happens with those? 2) Why an helium atom? Why not nitrogen, hydrogen, barium or whatever other element? All teachers always told me 'it emites helium atoms without electrons. These are known was alpha particles'. But why helium? What equation shows that the particles must be helium?