Scale: 10^-10 meters = 100 pm = 100 picometers

Carbon's Outer Shell

The inner electron cloud is represented by the gray sphere at the center. The fainter pattern surrounding these inner two electrons is the outer shell consisting of four electrons. The outer shell of electrons is where chemical reactions take place. The second shell of electrons is most stable when it contains a total of eight electrons. Since carbon has four electrons in its second shell, it can share four electrons with other elements, including other carbon atoms. This allows carbon to combine with other elements to make up a multitude of molecules. Carbon's tetrahedral bonding makes it an ideal building block for the complex molecules of living creatures.