Atom has its own structure. The nucleus of an atom is made of neutrons and protons. There are electrons that moves around or orbiting the nucleus. It can’t move away or closer to the nucleus because of the equal amount of positive and negative charges in an atom, which their attract each other. The outer layer of the atom, electron cells, is called the valence shell. The electron that found in the valence shell is called the valence electron(s).
The position of an element in the periodic table can also be determined by the drawings, or atomic structure of an atom. The period is determined by the amount of the electron cell that circled the nucleus while the group of the element is determined by the amount of valence electrons.
Electronic structure of an atom is consist of number of electrons in the inner shell, middle shell and outer (valence) cell.
Chemistry 