Question

how William crook discover electrons and Goldstein discover protons

Answer 1

Here is the answer to the question. May help you

Answer 2

Cathode rays- Discovery of electrons: In 1878 William Crooks carried out discharge tube experiments and discovered new radiations and called them cathode rays. Since these rays travel from the cathode towards anode. Later J.J Thomson studied on characteristics of cathode rays and concluded that cathode rays are negatively charged particles, now called electrons. The name electron was given by Johnson Stoney.

Discharge tube experiment: Canal rays Or Anode rays: In 1886, E. Goldstein carried out discharge tube experiments and discovered new radiations and called them canal rays. These rays were made up of positively charged particles and led to the discovery of proton.
The discovery of neutrons: Consider the element helium (He24). It was found that helium has two protons and two electrons however its mass was found to be four times that of Hydrogen. Similarly, the masses of some other elements were also found to be double or more than double the number of protons.

This problem was solved on the discovery of another particle ‘neutron’ by James Chadwick In 1932 by bombarding beryllium with alpha particles.

Be49 + He24 → C612 + n01
‘Neutron’ is a neutral particle with a mass equal to that of a proton and is present in the nucleus along with a proton.