Question

Electron was discovered by:
A. Thomson
B. Rutherford
C. Bohr
D. Chadwick

Answer 1

Hint: Electron is a negatively charged particle and has low mass. Electrons are discovered by carrying out the experiments in a discharge tube. Every atom contains electrons and they revolve around the nucleus in a fixed orbit.

Complete step by step answer:
- The experiment was carried out in a discharge tube at low pressure (0.01 mm of Hg).
- The discharge tube contains two electrodes of opposite charges.
- The oppositely charged electrodes are called cathode and anode.
- Cathode is positively charged electrode and anode is negatively charged electrode.
- A gas is passed through a discharged tube by applying high voltage to the electrodes results in the ejection of a negatively charged particle by the ionization of the gas.
- The negatively charged particles are called electrons.
- The discharge tube experiment was carried out by a physicist, J. J. Thomson.
- He began his experiments with cathode ray tubes.
- Therefore the electron was discovered by J. J. Thomson.

- So, the correct option is A.

Additional information:
- The electron is a negatively charged particle.
- The number of electrons present in an atom is nothing but the atomic number of the particular atom.
- The arrangement of electrons in the orbitals of the atom decides the chemical properties of the particular atom.


Note: Atoms contain protons, neutrons and electrons. Protons are positively charged particles and neutrons are neutral in nature. Both protons and neutrons are present in the nucleus of the atom. Electrons are going to revolve around the nucleus because of the positively charged nucleus.