Section 12.3
Lewis Structures
1.To learn to write Lewis structures
2.To learn to write Lewis structures for molecules withmultiple bonds
Objectives
Section 12.3
Lewis Structures
A. Writing Lewis Structures
•In writing Lewis structures we include only the valenceelectrons
•Most important requirement
–Atoms achieve noble gas electron configuration (octetrule, duet rule)
Section 12.3
Lewis Structures
A. Writing Lewis Structures
•Bonding pairs are shared between 2 atoms
•Unshared pairs (lone pairs) are not shared and not involvedin bonding
Section 12.3
Lewis Structures
A. Writing Lewis Structures
Section 12.3
Lewis Structures
B. Lewis Structures of Molecules with Multiple Bonds
•Single bond – covalent bond in which 1 pair of electrons isshared by 2 atoms
•Double bond – covalent bond in which 2 pairs of electronsare shared by 2 atoms
•Triple bond – covalent bond in which 3 pairs of electrons areshared by 2 atoms
Section 12.3
Lewis Structures
B. Lewis Structures of Molecules with Multiple Bonds
–A molecule shows resonance when more than one Lewisstructure can be drawn for the molecule
Section 12.3
Lewis Structures
B. Lewis Structures of Molecules with Multiple Bonds
–Boron – incomplete octet
Some Exceptions to the Octet Rule
–Molecules containing odd numbers of electrons – NOand NO2
