Which sub-particle was discovered LAST?
AElectron
BProton
CPhoton
DNeutron
Answer & Solution
Correct answer: D. Neutron
1. Thomson identified the electron in 1897.
2. Rutherford identified the proton around 1917.
3. Chadwick discovered the neutron in 1932.
4. So the neutron was discovered last among electron, proton and neutron.
_Source: Selina Concise Chemistry ICSE Class 9, Ch 4 'Atomic Structure'_
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