Question

Who discovered the electron?

Answer 1

1. Atom is made up of three subatomic particles that are protons, electrons, and neutrons.
2. Electrons are negatively charged particles whereas protons are positively charged particles. Neutrons have no charge.
3. J.J Thomson discovered electrons in the year 1897 by performing the cathode ray experiment.
4. He showed that cathode rays are charged particles.
5. The speed of cathode rays is much less than the speed of light.
6. He measured the charge to mass ratio of cathode rays.
7. Therefore, he concluded that cathode rays are $1/{1800}^{\mathrm{th}}$ the mass of hydrogen ions (protons).
8. These negatively charged cathode ray particles are known as electrons.
9. Electrons are negatively charged particles with zero mass.
10. The mass of an atom is the sum of protons and neutrons present in an atom.