Particles, subatomic arrangement within atom

The internal structure of the atom, that is, how the subatomic particles are arranged in space within the atom, is very complicated. All the protons, plus varying numbers of electrically neutral particles called neutrons, cluster inside the central nucleus. The 1... 

After discovering three subatomic particles in the early 1900s, scientists continued their quest to understand atomic structure and the arrangement of electrons within atoms. 

Even though protons and electrons had been identified as subatomic particles, the arrangement of these particles within the atom was not known. An atom was thought to be a uniform sphere of protons within which electrons circulated in rings. Only after the discovery of natural radioactivity did Ernest Rutherford (1871-1937) carry out experiments that led to the idea of a nucleus as a tiny core of the atom. 

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