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You work out the ( p.e.n, p.i.e, p.e.g ) diagram by:
1. filling in the proton and ( proton, electron, neutrons ) (all ( single, unstable, stable ) atoms - no. of protons = no. of electrons)
2. to work out the neutrons ( take, add ) the ( mass, proton, electron ) number away from the ( electron, proton, neutron ) number