1. RECAP: Chemical Bond
The forces that hold groups of atoms together and make them function as a unit
Bonding involves only the valence electrons
There are 2 types of bonds:
Ionic: Transfer of electrons from a metal and to a nonmetal
Covalent: Sharing of electrons between 2 nonmetals
Note: When 2 metals bond an alloy is formed
Electrons are transferred or shared to give each atom a noble gas configuration (stable octet)
This is known as the octet rule

2. Ionic Bonding

3. Ionic Bonding Metals Nonmetals Electron donors
Donate their valence electrons to become a positive ion (cation)
Nonmetals
Electron acceptors
Accept valence electrons to become a negative ion (anion)

4. Ionic Bonding

5. Ionic Bonding
The two oppositely charged ions are attracted to each other by a force called an ionic bond

6. NaCl Crystal Lattice Ionic compounds form solids at SATP.
Ionic compounds organize in a characteristic crystal lattice of alternating positive and negative ions.
All lattices are arranged so that each ion has the greatest possible number of oppositely charged ions close by, while keeping similarly charged ions as far away as possible

7. Crystal Lattice Structure
This explains why they have high melting points and are hard but brittle
Na+
Cl-

8. Ionic Compounds in Water
When ionic compounds dissolve, they separate into their ions
The free ions can now move and conduct electricity

9. Properties of Ionic Compounds
Structure:
Crystalline solids
Melting point:
Generally high
Boiling Point:
Electrical Conductivity:
Excellent conductors, molten and aqueous
Solubility in water:
Generally soluble

10. Covalent Bonding

11. Covalent Bonding
Between 2 Nonmetals
Share the available electrons

12. Properties of Molecular Compounds
Variable (low to high)
Solubility in Water
Nonelectrolyte
Electrical Conductivity
Low
Melting & Boiling Points
Variable (waxy to brittle)
Structure
Typically gases & liquids, but some solids
State at SATP