J. j. thomson is credited with which discoveries? select all that apply. subatomic particles neutrons isotopes electrons

I believed he was credited with making, subatomic particles, isotopes and electrons. Joseph John Thomson was credited with the discovery and identification of the electron, and with the discovery of the first subatomic particle in 1897. He also discovered isotopes, and invented a mass spectrometer and was awarded the Nobel Prize in physics in 1906. 

Do u have the n? or maybe the m?

The answer would be