Question

who and when invented electrons, protons and neutrons?

Answer 1

The discoveries of electrons, protons and neutrons were made by J. J. Thomson in 1897, Ernest Rutherford in 1911 and James Chadwick in 1932 respectively. 

Answer 2

JJ.Thomson's model of atom(Plum pudding model) led to the discovery of electrons.He discovered this in 1897.
JJ.Thomson thought that in a positively charged sphere electrons are embedded .


Ernest Rutherford's gold foil scattering experiment led to the discover of protons.
It was discovered in 1911.
In his experiment of passing alpha radiations through thin gold foil, he discovered that some of the radiation do not pass through it.
This meant that there is some positively charged particles in the nucleus.
He names these positively charged particles are protons.

In 1932, James Chadwick discovered neutrons.He worked with Rutherford, detected neutrons and measured their mass in an invisible game of billiards.