MCQ Detailed View

The neutron is a subatomic particle found in the nucleus of an atom along with protons. It has no electrical charge, which is why its discovery was delayed compared to protons and electrons. Unlike charged particles, the neutron does not interact with electric or magnetic fields, making it difficult to detect using conventional experimental methods available in the early 20th century.

The existence of the neutron was first proposed by James Chadwick in 1932 to explain discrepancies in atomic mass that could not be accounted for by protons and electrons alone. Before its discovery, scientists observed that atoms had more mass than could be explained by the number of protons, indicating the presence of another particle. The neutron’s neutrality made it invisible to techniques like cathode ray experiments or mass spectrometry, which rely on interactions of particles with electric or magnetic fields.

Other options are incorrect:

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  The neutron does move, as it has kinetic energy and participates in nuclear reactions.

  
  


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  Being a fundamental particle does not explain the delay; many fundamental particles, like the electron, were discovered earlier.

  
  


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  Its presence in the nucleus alone does not make it undetectable; it is the lack of charge that made experimental detection challenging.

  
  

Neutrons play a critical role in nuclear stability, isotopes, and nuclear reactions, including fission and fusion. Their discovery was pivotal in the development of nuclear energy and modern atomic theory. Understanding why the neutron was difficult to detect helps students appreciate both the experimental challenges and conceptual advances in atomic physics.

In summary, the discovery of the neutron was delayed because it does not carry any electrical charge, making it difficult to detect with early experimental techniques.