Question

Why was neutron discovered so late (in 1932 by James Chadwick) as opposed to protons and electrons which were discovered much earlier?

Answer 1

• Neutron is a neutral subatomic particle found inside the nucleus of an atom
• As neutron does not have any charge like proton and electron it was not easy to identify its presence.
• In 1932 James Chadwick proved the existence of neutrons by bombarding lighter elements (boron and beryllium) with alpha particles which then resulted in the emission of highly penetrating neutral radiation.
• This radiation was made incident with a hydrocarbon having high hydrogen content (paraffin wax).
• Protons were ejected from the paraffin wax.
• He observed the range of ejected protons and the interaction of this neutral radiation with many gases.
• He concluded that these neutral particles have a similar mass as that of neutrons and later it was named as neutrons.