Chemistry Reference
In-Depth Information
EXAMPLE 5.13
Draw an electron dot diagram for CO
2
, in which the oxygen atoms are both
bonded to the carbon atom.
Solution
Valence
Valence
electrons
electrons
Atoms
available
required
C
2 O
Total
1
4
4
1
8
8
2
6
12
2
8
16
16
24
The number of electrons to be shared is
24
16
8.
Put two pairs of elec-
trons between each pair of adjacent atoms:
O
C
O
(Incomplete)
Adding the other available electrons (8) yields the complete electron dot
diagram:
O
C
O
Be sure to check that all the atoms have the proper octets (duets for hydrogen
atoms) and that all valence electrons and no other electrons are shown.
O
C
O
Practice Problem 5.13
Draw an electron dot diagram for HN
3
,
hydrazoic acid.
EXAMPLE 5.14
Draw an electron dot diagram for formaldehyde, CH
2
O, in which the hydrogen
and oxygen atoms are all bonded to the carbon atom.
Solution
Valence
Valence
electrons
electrons
Atoms
available
required
2 H
C
O
Total
2
1
2
2
2
4
1
4
4
1
8
8
1
6
6
1
8
8
12
20
There are electrons shared. One double bond is needed for
8 electrons to be shared between the three pairs of atoms. The hydrogen
atoms cannot be involved in a double bond because their maximum number
of valence electrons is 2. Therefore, the double bond must be between the
20
12
8
