Chemistry Reference
In-Depth Information
Next, we will look at the Lewis dot diagram for carbon, which has an
electron configuration of 1s
2
2s
2
2p
2
. The valence shell of carbon contains a
total of four electrons (2s
2
2p
2
), so our dot diagram will show four dots. The
two s electrons will go on the left-hand side of the elemental notation, but
the two p electrons will split up, one per side, according to Hund's Rule.
Example 2
Show the correct Lewis dot notation for the element carbon.
C
Let's look at the Lewis dot notation for an atom of phosphorus. As you
recall, the following is the electron configuration and the orbital notation
that we found in the last lesson.
1s
2
2s
2
2p
6
3s
2
3p
3
Remember: The kernel, which, in this case, is the nucleus and all of the
electrons in the first two energy levels, will simply be represented by the
elemental symbol (P). The five valence electrons (3s
2
3p
3
) will be shown as
dots around the symbol, with no more than two dots per side.
Lewis Dot Notation for Phosphorus
P
Note that the sides, which represent the “p” orbitals, received only one
dot each, just as the circles representing those same orbitals in the orbital
notation for phosphorus received only one dot each. Hund's Rule instructs
us to find an empty orbital for each p electron, until we need to double them
up. Why, then, do the s electrons double up? Because there is only one s
orbital, the electrons in the s sublevel have no choice; they must share the
only s orbital.
Next, let's compare the electron configuration and orbital notation of
the element sulfur to its Lewis dot structure. Sulfur has six electrons in its
valence shell, so its dot diagram will show six dots. Does the diagram below
make it easier to see how the valence electrons are represented in the Lewis
dot structure?
