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Valence Electrons and Lewis Electron Dots of Atoms and Ions

 
 
G.N. Lewis, at the University of California at Berkeley devised a simple way to understand the nature of the chemical bond in both ionic and molecular compounds. His method rests upon focusing on the valence electrons of the elements. He represents these valence electrons as "dots" around the four sides of the elemental symbol.
 
Depending on how your teacher was taught, this may be slightly different. The first 2 valence electron go together (I was taught to place them on top), then one on each side going clockwise (3 o'clock, 6 o'clock then 9 o'clock).
Then doubling up going clockwise (3 o'clock, 6 o'clock then 9 o'clock). If you have 5 valence electrons as Nitrogen does, stop after 5 dots.
 
This order can be explained with the Auf Bau Principle and Hunds Rule.

 

Kernal- Represented by the symbol. It is the nucleus and the inner electrons of an atom or ion

Valence Electrons- Represented by the dots. The electrons in the outer most energy level of an atom or ion.

Now take this number and place a dot for each valence electron.

   Oxygen gets 6 dots.

Chlorine gets 7 dots.

NOTE****There is an order we fill the dots.

The first 2 go together (I was taught to start on top, so teachers start on the side), then you place one on each side before pairing them up.

So it looks like this, depending on how many valence electrons we have.

Real Examples

Ions

Ions have charges [and brackets].

A full octet of electrons (8 dots) is a stable configuration.  Oxygen would need 2 more electrons to be stable. Well that is what it does. Takes 2 electrons and becomes stable. It now has a 2- charge.

Metal ions are a little different. They get to 8 electrons by losing their valence electrons and using the full inner electron level.

It will have no dots, and a positive charge. Al had 3 valence electrons and loses them all. It will have a 3+ charge and look like this.

So for Ions, metal ions have no valence electrons and the nonmetal will have 8.

Metal are losers and are positive. Nonmetals gain and are negative.

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