How Does an Electron Dot Diagram Work?

Dots represent the valence electrons an element has to share during compounding.

Electron Dot Diagram

Electron dot configurations, also called Lewis structures, are used to help scientists build compounds out of chemical elements. For the sake of simplicity, use the two elements hydrogen (H) and oxygen (O) in this example. Together, H and O create water, or H20. The dots represent the valence electrons an element has to share during compounding. A valence electron is an electron that is in the outer energy shell and is in search of another element to balance its electric charge.

Writing the Electron Dot Configuration

Writing the electron dot configuration is simple. Determine the number of valence electrons the element has. For H, since it is in the first group of elements, it simply has one valence electron. To express this in Lewis structure format, write the element symbol H and place a dot on top. The dot represents the single electron ready for sharing.

Let's now do the same for O, which is in the sixteenth column across the top of the periodic table. Subtract 10 from the column number and you get the number of valence electrons that are in the outer shell of an O molecule. See the attached picture for the Lewis structure diagram of O.

Building Compounds with Electron Dot Configuration

The O molecule has two unpaired electrons. Unpaired electrons are those little guys on the right and bottom sides of the element symbol all by themselves. Those two electrons are looking for other electrons to pair with and H is the perfect example. The single electron of H bonds with one of the single O electrons. Once the O molecule pairs with two H molecules, each element has a completed outer energy level and becomes stable. See the attached picture for an example of a Lewis structure diagram for a water (H20) molecule.

Resources

• Electron Dot Diagram