Nucleus is at the heart of nuclear and particle physics, providing insight into the fundamental constituents of matter and the strong force that binds them together. This article aims to delve into the essential aspects of nuclei, exploring their constituents, intrinsic properties, and quantitative facts about their mass, radii, charge density, and matter density. By examining experimental methods used to determine these properties, we gain a deeper understanding of the nature of atomic nuclei.
The electron structure was understood even before the structure of Nuclei. Reason being the forces that held the electrons to their atoms are very small as compared the forces that are responsible for the stability of Nucleus. The chemical phenomenon which we study in chemistry arises from the interactions of electrons of atoms corresponds to very low energies in few electron volts. Whereas the Nuclear process of fission and fusion corresponds to energies in Mega-electron volts.
A Nucleus of a Hydrogen atom consists of only a proton with charge e+, however few of the Hydrogen atoms contains a neutrons as well.
Ordinary Hydrogen à 1 proton
Deuterium à 1 proton + 1 neutron
Tritium à 1 proton + 2 neutron (Radioactive)
The atoms having equal Number of Protons but different number of neutron are called the isotopes of the element.
Atomic Masses of Nucleus
Atomic mass refers to the mass of neutral atoms, not only nuclei. The atomic mass includes the mass of proton plus neutron plus the mass of its Z electrons. Atomic masses are expressed in mass unit (u). Which is so defined that the mass of a 126C atom, the most abundant isotopes of carbon is exactly 12u.
1u=1.66054 x 10-27 kg
Isotopes have different atomic masses as their nuclear composition differ. For example the 35 17C
And 37 17C are two isotopes of chlorine. Which yields the average atomic mass of 35.46u. As the electron structure of two isotopes is same their properties like colour, odour and ability to form chemical bonds remain same but properties which depends on the mass of atom differ like boiling point and freezing points.
Various techniques have been utilized to explore the structure of nucleus but two of them 1) Electron Scattering and 2) Neutron Scattering remain the most widely used.
The electron scattering uses high energy electrons bombarded on the nucleus of atom. Electron scattering gives us information about the distribution of charge in a nucleus as they interacts through the Coulomb`s forces. The Neutron Scattering used neutrons and gives us information about the distribution of nuclear matter. Neutrons interacts through the Strong nuclear forces.
The results of experiments have suggested that the Radius (R) of an atom is directly proportional to its Mass number that is its number of Nucleons (A).
The relationship is given by
R=R0A1/3 where R0 is a constant.
The density of Nucleus is found to be extremely large that it is comparable to the density of a neutron star. A neutron star packs the amount of mass of about 1.4 to 3 suns into a sphere of radius of 10Km only.
In conclusion, the study of the general properties of nuclei provides a deep understanding of the fundamental constituents of matter and their interactions. By investigating the constituents, intrinsic properties, and quantitative facts about nuclei, physicists gain insight into the strong force that governs their behaviour. The experimental determination of mass, radii, charge density, and matter density has been made possible through innovative techniques that continue to expand our knowledge of the atomic nucleus. This knowledge not only informs nuclear and particle physics but also has applications in fields such as nuclear energy, medical imaging, and astrophysics. As our exploration of nuclei continues, we uncover the intricate details of the subatomic world that shape our understanding of the universe.