1. Ch. 8-2 II Nature of Covalent Bonding

2. Coordinate Covalent Bond
One atom contributes both bonding electrons

3. Coordinate Covalent Bond
In structural formula, arrow points from donating atom to the receiving atom
Once formed, acts like any other covalent bond

4. Polyatomic Ion
Tightly bound group of atoms with a positive or negative charge that behave as a unit
Typically involves a coordinate covalent bond (along with normal covalent bonds)
Usually requires the addition of electrons (for negatively charged ions)

5. Polyatomic Ion
Tightly bound group of atoms with a positive or negative charge that behave as a unit
Ammonium, NH4+
Sulfur trioxide, SO32-

6. Polyatomic Ion
Negatively charged polyatomic ions are anions & part of ionic compounds (metal cations balance overall charge to become neutral)
Sodium hydrogen carbonate, NaHCO (Sodium Bicarbonate)
Potassium cyanide, KCN

7. Resonance Structures
Result when there is more than one valid electron dot structure for a molecule
Different placement of electron pairs
Not ATOMS
Indicate with double arrow
All bond types are the same
Molecules DON’T flip flop back and forth
Ozone, O3

8. Bond Dissociation Energies
Energy required to break the bond between two covalently bonded atoms
Larger values indicate stronger bonds

9. Bond Dissociation Energies

10. Exceptions to Octet Rule
1. Odd total number of Valence Electrons
Nitrogen dioxide, NO2

11. Exceptions to Octet Rule
2. Fewer than 8 Ve
3. More than 8 Ve
Boron Trifluoride, BF3
Phosphorus pentachloride, PCl5
Sulfur Hexafluoride, SF6
WHICH ROW???