Atoms are the small particles of which every element is made up of. The atom possesses the properties of its element.
Every atom consists of nucleus at its center core and electrons around the nucleus.
Discovery of Nucleus
Initially, it was faraday who used the word śnucleusť in the year 1704 which describes the atoms central point. Later Rutherford discovered positively charged nucleus at the center of the atom.
The nucleus of an atom comprises of positive charge which consists of positively charged protons and neutrons which are of neutral charge. So, protons and neutrons are together called as nucleons and the total charge of the nucleus is positive. The total mass of the atom is the collective mass of the nucleons and the nucleus size is of the order of Fermi meters which are smaller than that of the atom.
The following figure shows the nucleus of an atom.
Stability of the Nucleus
Atomic number is the total number of protons in an atom and the atomic mass number is the total number of protons and neutrons. The neutron number relative to the proton number gives the nucleus stability and in case of heavy nuclides, they acquire stability by undergoing decay.
Size of the Nucleus
The size of the nucleus varies from light element to heavier element that is for light element like hydrogen, the nucleus size will be around 1.5 fm and the nucleus size of a heavier element like uranium, the nucleus size will be 15 fm.