In 1932, James Chadwick discovered that some particles in the nucleus have no charge at all. He called them neutrons. Electrons (negatively charged particles) have been shown to orbit the nucleus at distances.

In 1932, James Chadwick made a significant discovery in the field of nuclear physics. He found that the nucleus of an atom, previously known to contain positively charged protons, also contained particles that had no charge. These neutral particles were aptly named "neutrons".

In addition to the nucleus, atoms also contain negatively charged particles known as electrons. These electrons are not located in the nucleus, but instead, they orbit around the nucleus at varying distances. These orbits are often referred to as "energy levels" or "shells".

The discovery of neutrons and the understanding of electron orbits were crucial in developing the modern model of the atom and have greatly contributed to our understanding of the physical world.