Question

Neutron was discovered by
A. Rutherford
B. Anderson
C. Chadwick
D. Millikan

Answer 1

Hint: Neutron is a subatomic particle having zero charge and mass almost equal to the mass of proton. Neutrons are found inside the nucleus and neutrons and protons together are known as nucleons.

Complete step by step answer:
The correct answer is option B. Neutron was discovered in 1932 by Chadwick.
Before the discovery of neutrons, it was known that the centre of the atom called nucleus contains charged particle protons and almost all the mass of atom and electrons revolve around the nucleus in circular orbits.
The problem was that the total mass of the nucleus was recorded to be more than the mass of all protons in the nucleus. Scientists speculated additional protons in the nucleus to account for the mass of the atom. Rutherford proposed that there might be another particle in the nucleus formed by combining protons and electrons but it couldn’t be confirmed experimentally. Chadwick started to work on these neutral particles as suggested by Rutherford.
Chadwick had published his paper on the existence of neutrons after experimenting merely for two weeks working on neutrons. It was established by next year that neutrons do exist.
Additional information:
Rutherford discovered the atomic nucleus and gave Rutherford a model of atom.
Carl Anderson discovered the existence of a positively charged particle called positron having the same mass but opposite charge of the electron. Positron is an antiparticle of an electron.
Millikan discovered the charged particle electron through his famous oil drop experiment.

Note: The discovery of neutrons was later than other charged particles like electron and proton because it is charged less and goes undetected in experiments unless it interacts with some other matter.