1. Properties of Ionic and molecular compounds

2. What is an Ionic compound?
Neutral compound
Formed from a metal and a non-metal
Metal is a cation (positively charged)
Exception: Ammonium ion NH4+
Non-metal is an anion (negatively charged)
Ionic compounds are polar
Electrons are transferred!
Bond is easily broken
Can typically be broken by dissolving the compound in water

3. Properties of Ionic compounds
Form crystals
High melting and boiling points
Hard and brittle
Conduct electricity ONLY WHEN DISSOLVED IN WATER!
Do NOT conduct electricity in their solid form

4. Examples of ionic compounds
TELL ME SOME!

5. Ionic compound formula writing
THEY ARE NEUTRAL AND HAVE NO CHARGE!
Balance out charges from cation and anion to form a neutral compound
Find common factor between charges
Criss-cross charges (make sure they are reduced)
Superscripts tell you the charge
Subscripts tell you the number of atoms
Polyatomic ions = Ions formed from more than one element
Treat polyatomic ions as a group or whole unit
Need parentheses ONLY when more than one polyatomic ion unit is required to make compound neutral
Al+3 SO4-2
Al2(SO4)3

6. Ionic compound naming Cations are written FIRST followed by the anions
Cations are named by the name of the element
Ex: name of Sodium’s ion is…you guessed it, SODIUM ION
Anions are named by the name of the element but…
They end in –ide
Ex: Chlorine ion = CHLORIDE
Cations that form multiple charges need to have the Roman numeral in the name
Ex: Iron (II) chloride

7. Oxygen is a Special Case
Atom bonded to 3 or 4 oxygens
Ends in –ate
Nitrate (NO3-1)
Phosphate (PO4-3)
Sulfate (SO4-2)
Atom with 1 less oxygen than the –ate form
Ends in –ite
Nitrite (NO2-1)
Phosphite (PO3-3)
Sulfite (SO3-2)
Hypo- and Per- prefixes
ClO3-1 (Chlorate)
ClO2-1 (Chlorite)
ClO-1 (Hypochlorite)
ClO4-1 (Perchlorate)

8. What is a Molecular Compound?
Neutral compound
Formed from TWO NON-METALS!
Can be polar or non-polar
ELECTRONS ARE SHARED BETWEEN THE 2 (or more) ELEMENTS!
Lewis dot structure helps with representing the bond(s)

9. Properties of molecular compounds
Most have LOW melting and boiling points
Tend to be soft and/or flexible
State of matter of most molecular compounds
More flammable than ionic compounds
Carbon, hydrogen, oxygen
Don’t dissolve well in water (usually) and are non-conductive

10. More examples of molecular compounds

11. Molecular compound formula writing
Draw Lewis dot structure
SHARE ELECTRONS SO EACH ELEMENT HAS 8!
OCTET RULE

13. Let’s practice!

14. Molecular compound naming
Use Greek prefixes
First element is still just the name of the element
Second element ends in “ide”
If first element is only one, mono not needed!
If second element is one, mono IS needed.
CO2
H2O
SF6
Carbon dioxide
Dihydrogen monoxide
Sulfur hexafluoride

15. Types of Molecular bonds
Different bonds
Single bond
1 line
2 electrons are shared
Double bond
2 lines
4 electrons are shared
Π-bond
Triple bond
3 lines
6 electrons are shared

16. Types of Molecular Bonds cont.
Two types of molecular bonds
Covalent bond
Electrons are shared equally
All diatomic molecules
Polar covalent bond
Electons are shared unequally
More electronegative element pulls electrons toward itself
Dipole

17. Predicting the type of bond
The Rules of Predicting the Bonds
If the difference between 2 elements is 0 to 0.5
Nonpolar covalent
If the difference between 2 elements is 0.6 to 1.6
Polar covalent
If the difference between 2 elements is greater than 1.6
Ionic

19. Saturated and Unsaturated Bonds
Both involve covalent bonds
Saturated Bonds
No double or triple bonds in the chain of carbons
Unsaturated Bonds
Double or triple bonds exist in the chain of carbons