Question

Who discovered the neutron?
1. James Chadwick
2. J J Thomson
3. Rutherford
4. Einstein

Answer 1

Correct Answer - Option 1 : James Chadwick

CONCEPT:

• The discovery of the neutron is credited to James Chadwick.
• A neutron is a neutral particle found inside the nucleus and has no charge.
• The below table shows the discovery of other subatomic particles also:

	Discoverer	Year of Discovery
Proton	E. Rutherford	1909
Neutron	James Chadwick	1932
Electron	J.J. Thomson	1897

EXPLANATION:

• The discovery of the neutron is credited to James Chadwick.
• James Chadwick shot alpha particle radiation at a very thin sheet of beryllium.
  • This radiation of alpha particles knocked neutrons out of the beryllium atoms.
  • These neutrons then knocked charged protons out of a disc of wax which was picked up by a detector.
  • This led to the invention of neutrons.
• So the correct answer is option 1.