ABSTRACT
The nucleus remains unchanged during chemical reactions. Chemical processes are based on electron behavior, such as exchange or sharing of electrons between atoms. The electronic structure of the atom, thus, provides the basis for the chemical behavior of the elements. Electrons in atoms are described according to the theory of quantum mechanics, which uses the concept that electrons in the atom can be described by their wave nature (wave/particle duality). An electron in an atom is associated with a spin. The spin can be thought of as clockwise or counterclockwise and is measured by its magnetic field (“north pole” or “south pole”). The electron is assigned a fourth quantum number; a spin quantum number with the symbol ms. The electron configuration of an element is the full description of all orbitals occupied by all the electrons in the atom of the specific element.
