An atom is composed of a positively-charged nucleus, with a cloud of negatively-charged electrons surrounding it, bound together by electrostatic force.
😊Protons and neutrons are bound together to form a nucleus by the nuclear force.
😊After the discovery of the neutron in 1932, models in support of a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg.
😊Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud.
The branch of physics concerned with the learning and understanding of the atomic nucleus, including its composition and the forces which bind it together, is called nuclear physics.
Source:
[1] Wikipedia Contributors. “Atomic Nucleus.” Wikipedia, Wikimedia Foundation, 4 Nov. 2020, en.wikipedia.org/wiki/Atomic_nucleus. Accessed 5 Nov. 2020.
[2] Engin_Akyurt. “Abstract Light Color – Free Photo on Pixabay.” Pixabay.Com, 16 June 2017, pixabay.com/photos/abstract-light-color-color-image-2408490/. Accessed 5 Nov. 2020.