Fundamentals: Beta decay

An atom P decays into Q emitting a beta particle. The energy released is simply mass of atom P - mass of atom Q multiply by square of speed of light. Consider P to have mass number 28 and 13 proton and 13 electron. Atom Q has mass number 28 and 14 proton and 14 electron . One neutron in P has converted into proton plus an electron . Hence the beta particle emitted is already included in atom Q. So P = Q + e + Energy. Energy released = (mass of P - mass of Q )xc2. No need to deduct mass of electron . The resulting Q is positively charged as the electron is released (outside of atom)