Image of discovery of atomic nucleus.
Image of discovery of atomic nucleus


In the article, we will discuss about the discovery of atomic nucleus. We will discuss about the Rutherford and the gold foil experiment. Atomic nucleus have protons and neutrons inside while electrons surround the nucleus, continuously revolving around the nucleus. The four quantum numbers determine the energy, shape, orientation and spin of electrons in the orbitals. The atomic nucleus act as a central core of the atom and play vital role during bonding of electrons. The discovery of nucleus revolutionized the atomic physics and chemistry, that enable the scientists to reveal the complexities of atom.


The discovery of atomic nucleus, the central core of an atom, was a groundbreaking achievement in the field of atomic science. This pivotal discovery revolutionized our understanding of the structure of matter and laid the foundation for further advancements in nuclear physics. In this article, we will dive into the history of the discovery of the nucleus, exploring the key scientists involved and the experiments that led to this remarkable breakthrough.


One of the key figures in the discovery of the nucleus was Ernest Rutherford, a New Zealand-born physicist. In 1911, Rutherford conducted the famous gold foil experiment, which provided the first experimental evidence for the existence of the atomic nucleus. Rutherford bombarded a thin gold foil with alpha particles and observed their scattering patterns. Contrary to the prevailing belief that atoms were uniformly distributed, Rutherford’s experiment revealed that most of the alpha particles passed straight through the foil, while a small fraction were deflected at large angles. This unexpected result led Rutherford to propose the existence of a dense, positively charged nucleus at the center of the atom.

Image of Rutherford's experiment.
Image of Rutherford’s experiment


Prior to Rutherford’s experiment, the prevailing model of the atom was the “plum pudding” model, proposed by J.J. Thomson. According to this model, the atom was thought to be a uniform, positively charged sphere with negatively charged electrons embedded within it. Rutherford’s gold foil experiment disproved this model and paved the way for the development of a new atomic model that incorporated the concept of a nucleus.

Plum pudding model.
Plum pudding model.


Another significant milestone in the understanding of the nucleus came in 1932 when James Chadwick, a British physicist, discovered the neutron. Chadwick’s experiments involved bombarding beryllium with alpha particles, which resulted in the emission of a previously unknown neutral particle. This discovery provided further evidence for the existence of a nucleus, as the neutron was found to be an uncharged particle located within the nucleus, alongside protons.


Following the discovery of the nucleus, further advancements in nuclear physics continued to deepen our understanding of atomic structure. The development of quantum mechanics and the discovery of subatomic particles, such as quarks, further expanded our knowledge of the nucleus and its constituents.


The discovery of the nucleus was a pivotal moment in the history of atomic science. Ernest Rutherford’s gold foil experiment and subsequent research by James Chadwick laid the foundation for our current understanding of atomic structure. The existence of the nucleus, a dense core containing protons and neutrons, revolutionized our understanding of matter and paved the way for further advancements in nuclear physics. Today, the study of the nucleus continues to be a vibrant field of research, with applications ranging from energy production to medical diagnostics and treatment.

Keywords: Revolution of atomic and nuclear physics.


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Chadwick, J. (1932). Possible Existence of a Neutron. Nature, 129(3252), 312.

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Tipler, P. A., & Llewellyn, R. A. (2002). Modern Physics. W. H. Freeman and Company.

H. Geiger & E. Marsden (1909), On a Diffuse Reflection of the alpha-Particles
Proc. Roy. Soc., 82 (557): 495-500.

E. Rutherford & H. Geiger (1908), An Electrical Method of Counting the Number of alpha-Particles from Radio-Active Substances
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