The Foundations of Chemistry

For H 2 SO 4 ,

SNA 44  32

12 electrons shared (6 pairs of eshared)

For ClO 4 ,

SNA 40  32

8 electrons shared (4 pairs of eshared)

For NO 3 ,

SNA 32  24  8 eshared (4 pairs of eshared)

3.Place the Selectrons into the skeleton as shared pairs.Use double and triple bonds

only when necessary. Lewis formulas may be shown as either dot formulas or dash

formulas.

Dot Formula Dash Formula

(“bonds” in place, (“bonds” in place,

Formula Skeleton but incomplete) but incomplete)

H 2 SO 4

ClO 4 

NO 3 

4.Place the additional electrons into the skeleton as unshared (lone) pairsto fill the

octet of every A group element (except H, which can share only 2 e). Check that

the total number of electrons is equal to A, from step 2. Examples:

For H 2 SO 4 ,

Check: 16 pairs of ehave been used and all octets are satisfied. 2     16  32 e

available.

For ClO 4 ,

O

O

O O

O

O

OOCl



Cl



or

O

O

HHOOS or S

O

O

HOO H

O

O O

N



O

OO

N



O

OO

N



O

O

OOCl



O

O

OOCl



O

O

OOCl



S

O

O

HOO H

O

O

HHOOS

O

O

HHOOS

C, N, and O often form double and
triple bonds. S can form double bonds
with C, N, and O.

284 CHAPTER 7: Chemical Bonding