ABSTRACT
The nucleus of an atom is composed of protons and neutrons bound together by shortrange nuclear forces. The protons and neutrons are collectively known as nucleons. The charge on a proton is equal to +1 atomic charge unit and neutrons have zero charge. The number of protons in the nucleus is called the atomic number, or atomic charge, of the atom and has the symbol Z. The atomic number is unique to each element. In a neutral atom the positive charge of the protons in the nucleus is balanced by an equal number of negatively charged electrons in orbitals surrounding the nucleus.
