HOW TO DRAW LEWIS STRUCTURES!
HOW TO DRAW LEWIS STRUCTURES!A STEP BY STEP TUTORIAL
Kyla SmartMichael BurnetteNick Ryan LorRoss SisonSowhat are
Lewis Structures?Lewis Diagrams are used to describe the structure
of covalent molecules. They use a simple and clear notation to
represent the valence shell electrons of all of the atoms in a
molecule.How to Create a Lewis StructureStep 1.Add up the number of
valence electrons present in all of the atoms in the molecule. To
determine how many valence electrons an atom has you can use the
periodic table. The number of valence electrons is equal to the
group number of the element. Tip: To move faster you can multiply
the group number of the element with the number of atoms of that
element in the moleculeExample: Step 1Assignment: Draw a Lewis
structure of the molecule O3There are 3 oxygen atomsOxygen is found
in group 6Therefore Oxygen has 6 valence electrons3 X 6 = 18There
are 18 valence electrons in O3Step 2.Draw a rough structure
Pick a central atom and connect the remaining atoms with a
single bond to the central atom
The central atom is usually the first atom in the
moleculeExample Step 2.O-O-OStep 3.Place dots around all of the
atoms.These dots represent unpaired valence electronsA single bond
accounts for 2 valence electronsMake sure that each atom has 8
valence electrons around it(there are a few exceptions to this rule
such as Hydrogen)Example Step 3.O-O-O
Represents the valence electronsStep 4Count up the number of
electrons present in the atomEach bond represents 2 electronsCheck
to make sure that this number is equal to the number determined at
the beginningIf it matches, then YOURE DONEIf not, move on to step
5Example Step 4.O-O-O
There is a total of 20 valence electrons in this diagram. In
step 1 we decided that there needed to be 18 valence electrons
.This diagram has 2 extra valence electronsStep 5To lower the total
number of electrons, take 2 electrons off of two atoms that are
bonded together and place another bond between those two atoms.
Each time you do this, it will lower your electron count by 2Do
this until the number of electrons is equal to the number
determined in step 1.Make sure that the molecule is as symmetrical
as possible. For example, do not have a triple bond and a single
bond when you could have a two double bondsExample Step 5.O-O=O
Remove a pair of valence electrons from the central atomRemove a
pair of electrons from one of the outer atomsThe two atoms that you
have removed the electrons from are now sharing, not one but two
pairs of electrons and therefore are double bonded
The diagram now has 18 valence electronsCongratulations, this
number matches the number from step 1.A Helpful Hint
HONCHalogens/HydrogenOxygenNitrogenCarbon1234This diagram can help
you remember the number of bonds that each atom tends to form.
Hydrogen & Halogens tend to form 1 bondOxygen tends to form 2
bondsNitrogen tends to form 3 bondsCarbon will form 4 bonds (with
some exceptions)AlsoIf your compound has a charge on it (aka is an
ion), add up the total number of electrons present and either add
extra electrons if you have a negative charge or subtract electrons
if you have a positive chargeDraw the structure of the compound so
that the total number of bonds and lone pairs adds up to the
correct amount of electronsDraw brackets to the left and right of
the Lewis Structure and put its charge to the right of the top of
the right bracketExampleNO3-O=N OO
YOURE DONE!
Sha_Na_Na_-_Goodnight_SweetheartThe SpanielsThe Golden Age of
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