Neutrons were discovered in 1932, more than 10 years after the existence of isotopes was confirmed. what property of electrons and protons led to their discovery? suggest a possible reason why neutrons were the last of the three classic subatomic particles to be discovered.

Protons and neutrons are the sub-atomic particles present in the nucleus of an atom where as electrons are present revolving round the nucleus in orbits. Electrons are negatively charged, protons are positively charged where as a neutron is a neutral species. It is the presence of electric charge that lead to the discovery of electrons (negative charge) and protons (positive charge), while it took time to discover neutral as they were electrically neutral species. Neutrons carrying no charge were not detected easily by passing electromagnetic radiations. Therefore, neutrons were the last of the three subatomic particles, to be discovered.