The Octet rule is one of the rule which is applied to study the energy levels of electrons. It also helps in identifying the valence electrons and the ways to recognize it within the periodic table. before explaining any rule, it is important to explain what are the different composition present within an atom. Atom are made up of neutrons which are neutral in charge and protons which are positive in charge. The protons and neutrons lives within the nucleus and in the orbits that revolves like the electrons which are negatively charged. The proper arrangement and categorization of the elements is easily done in the periodic table. Atom always try to gain the stability. They try to achieve stability. The term stability explains that the outermost energy level of the atom is complete. It also states that outermost shell is completely filled with the electrons. The highest occupied energy level is known as the valence shell. The characteristics of the elements is easily determined by the number of valence electrons. The word octet itself denotes eight. According to the octet rule, it can be stated that the outermost valence shell of the electrons must be filled with eight electrons. In order to achieve the eight electrons in the outermost shell the atoms will try to loss or gain electrons to get stable by having eight electrons in the valence shell. The electrons are gained when the atoms are bonded with another atom. The bonding can be made between the same elements or different elements. For example, the bond between the two atom of oxygen for the formation of O2. The bond between the different atoms for the formation of H2O is also an example of the ways atoms share their electrons to achieve stability. There are two exceptional cases that is in case of hydrogen and helium where there are two electrons in the outermost shell and they are stable.

According to the Lewis structure the representation is made with the help of dotted structure. Lewis structure is one of the quick method where diagram is made to show the electrons present in the valence shell. In the Lewis structure the symbol is used to represent the nucleus. The electrons which are valence is represented with the help of the dots. The dots are represented in the form of pair. The diagram or the structure are helpful as it helps in the identification of how the elements will react within a chemical reaction. In order to draw the Lewis structure, it is necessary to identify that how many valence electrons is present in the element. One of the easiest way to identify is by recognizing the elements group numbers on the periodic table which help in giving the number of valence electrons. The electrons which are left forms the lone pairs or forms the shared electron pairs in order to gain the stability by fulfilling the octet rule. However, the Lewis structure is also known as the electron- dot structure.