How to Diagram Bonds Using the Lewis Dot structure
The following are more examples of bonding diagrams. Try them on your own first and then check your answers. Note the additional list of instructions provided.
Steps to Diagramming a Reaction (Lewis Dot structure)
1.
Determine the type of bond a.
If the elements are metals & nonmetals it will be ionic b.
If the elements are just nonmetals it will be covalent (careful of Hydrogen)
2.
Determine what will happen to the electrons a.
In an ionic bond the metal will transfer its outer electron(s) to the nonmetals outer level b.
In a covalent bond the outer energy levels will overlap and will share the required electrons
3.
Under the “Reactants” heading draw the Lewis Dot diagrams of the atoms involved but remember: a.
Write the element symbol (no circles) b.
Use dots for the valence e
s only (max of 2 per side) c.
Try to get the valence electrons that interact to face each other in the diagrams d.
If more atoms are needed to become stable add them e.
If there are more than 2 atoms, arrange the dots for greatest convenience f.
If it is an ionic bond draw an arrow for each e- transferred from the metal to the empty space in the nonmetal g.
If it is a covalent bond circle the pairs of electrons that are shared (1 circle for each pair)
4.
Under the “Products” heading draw the compound that is formed a.
If it is an ionic bond i.
the metals will lose their valence electrons (blank) and label the metal with its positive ionic charge = # of electrons lost ii.
the nonmetal will get the electron(s) from the metal and fill up their blank spaces and label the nonmetal with its negative ionic charge = # of electrons gained iii.
The sum of the ionic charges must add up to 0 b.
If it is a covalent bond i.
Merge the atoms so the shared pairs line up for the Lewis Dot structure and each element will then have a stable valence number (count shared electrons in both elements) ii.
The number of electrons an atom will share is usually the number of additional electrons it needs to make the octet in its outer ring. iii.
Covalent Bonds do not have ionic charges
5.
Label the Type of Bond – Ionic or Covalent
Try the following Reactions and then check your answers below:
1.
Diagram the reaction of lithium and fluorine to form LiF
2.
Diagram the reaction of beryllium and oxygen to form BeO
3.
Diagram the reaction of sodium and oxygen to form Na
2
O
4.
Diagram the reaction of bromine and bromine to form Br
2
5.
Diagram the reaction of oxygen and oxygen to form O
2
6.
Diagram the reaction of nitrogen and nitrogen to form N
2

Diagram the reaction of lithium and fluorine to form LiF
Step 1 – metal & nonmetal = ionic
Step 2 – Li loses e
-
to F
Reactants

Li
Step 3
F
– draw Lewis
Dot models & draw an arrow to show the electron transfer
Diagram the reaction of beryllium and oxygen to form BeO
Reactants 
Ionic bond
Be O
Products
L
+ charge - charge i
+
Products
F
Step 4 – draw compound – note: no e
-
on metal, all e
-
on nonmetal and place ionic charges on ions
Li lost 1 e
-
so +1
F gained 1 e
-
so –1
Total= +1 –1 = 0
Step 5 – Ionic bond forms (opposites attract)
Be
+2
+2 charge
O
-2
-2 charge
Diagram the reaction of sodium and oxygen to form Na
2
O
Reactants

Ionic bond
Na O Na Na
+
+1 Charge
Products
O
-2
-2 Charge
Na
+
+1 Charge

Diagram the reaction of bromine and bromine to form Br
2
Step 1 – nonmetal & nonmetal = covalent
Step 2 –Each Br needs 1 e
-
to complete octet so each brings 1 e
-
to share
Reactants

Product
Step 3 – draw Lewis Dot models & circle the pair of electrons that will be shared
Step 5 - Covalent Bond forms or
Diagram the reaction of oxygen and oxygen to form O
2
Reactants

Covalent Bond
O O
Product
O O or
Step 3 –Each O needs 2 e- to complete octet so each brings 2 e- to share
Diagram the reaction of nitrogen and nitrogen to form N
2
Reactants

Covalent Bond
N
Step 3
N
–Each N needs 3 e- to complete octet so each brings 3 e- to share
Product
N N
or
O
Step 4 – draw the Lewis
Dot compound allowing sharing electrons to form a
“combined space” between the elements. If more than
1 pair of electrons are shared for one side, push shared electrons next to each other like in O
2
below.
N
O
N