Drawing Electron Dot Diagrams and Lewis Dot Diagrams

Let us examine an example of an electron dot or Lewis diagram.

1. The centre of the diagram, the atomic symbol represents the nucleus.
2. Each dot represents an electron in an electron dot diagram. These are only the valence electrons, or the electrons in the outermost shell.
3. In a Lewis diagram, lines represent a  bond between two electrons.

Here is an example. Because Nitrogen has 5 valence electrons and hydrogen has 1. Hydrogen needs 1 electron to become full and nitrogen needs 3.
Therefore, in NH3, N and H share electrons so that H is full with 2. and N, being surrounded on 3 sides gets 3 electrons.


In a structural diagram, electron bonds can be represented with a ---(line)


In Ionic compounds:

As you can see here, sodium has 1 valence electron and chlorine has 7.
Sodium and chlorine both want to become happy, and they are attracted to each other. The sodium loses its valence electron and becomes (+)1 charge. Chlorine takes this electron and fills it valence shell, giving it a (-1) charge.  Therefore, this is how the Lewis diagram is shown.



Extra help!

http://www.youtube.com/watch?v=y6QZRBIO0-o
http://www.youtube.com/watch?v=QKoA3fZ29B0