1. Inside the atom

Nucleon - name used for a particle (proton or neutron) in the nucleus

Charge/CCharge relative to protonMass/kgmass relative to proton
Proton+1.60 x 10^-1911.67 x 10^-271
Neutron001.67 x 10^-271
Electron1.60 x 10^-19-19.11 x 10^-310.005

Specific charge = charge/mass

Atomic number = z

Nucleon number = A

Isotopes are atoms with the same number of protons but a different number on neutrons in the nucleus.