im sure its a simple question but i dont know thanks
If you know it's either a proton or an electron (but no other kind of particle), then all you need to do is measure its charge, or its mass.
Hmm.. as a real life experiment?
Magnetic fields and electric fields can do this very easily.
If you apply an electric field, a proton will go in the direction of electric field lines, and an electron will go the reverse.
Magnetic fields: right hand rule.
Otherwise, chroot is right. Electrons have negative charge. Protons have positive. A proton weighs more than an electron.
Separate names with a comma.