Lewis Dot Structures

Lewis dot diagrams are very useful in chemistry. They help chemists visualize the important valence electrons that do all of the bonding work in compounds. Chemistry is a very abstract science; therefore, having the ability to visualize what is happening on the atomic level with a representative diagram serves an important role. Dot diagrams provide information on what type of bond will form and the corresponding structure that will result.

When drawing the dot diagrams for the representative elements, it becomes evident that there is a periodic trend for the number of valence electrons in a neutral atom of an element. Group One elements have one valence electron, Group Two elements have two valence electrons, and Group Thirteen elements have three valence electrons and so on through Group Eighteen. Group Eighteen, or the noble gases, are extremely stable elements. This means that their outer energy shells are filled with electrons; however, helium is special. It has a filled outer energy level, but the first energy level holds a maximum of only two electrons, so helium has two valence electrons.