This is a limited theory on chemical bonding nature and electronic structure but provides a simple viewpoint towards the formation of any molecular composition.

Lewis Structure is a diagrammatic representation of any given molecule with the help of the constituent atoms and the position and arrangement of electrons to form bonds and lone pairs. The electrons in the outermost shell which determine the valency are known as valence electrons. Inside an atom, we have the positively charged nucleus surrounded by electrons in their shells forming a negatively charged cloud.