1. Polyatomic Ions

2. What is a Polyatomic Ion?
= many or several
Atomic
= atoms
So, a polyatomic ion is an ion with more than one atom
The charge is on the WHOLE ION not the individual atoms

3. OH- (O2-H+) (OH)- or OH- Example: Hydroxide Which is really...
So the total charge for the whole ion becomes 1-
(OH)-
But Remember: the negative charge belongs to the entire molecule (the OH) and not just the H.
or OH-

4. There are several polyatomic ions that unfortunately you just have to memorize...
(NO3)- 1-
(NO2)- 1-
(OH)- 1-
(HCO3)- 1-
(ClO3)- 1-
(CO3)2- 2-
(SO4)2- 2-
(SO3)2- 2-
(PO4)3- 3-
(PO3)3- 3-
(O2)2- 2-
(NH4)+ 1+

5. TERNARY Compounds

6. Polyatomic Ions can form TERNARY COMPOUNDS
Compound = 2 or more different elements
Therefore, ternary compounds are compounds composed of 3 different elements

7. Example #1: Sodium Hydroxide
(Metal ion) +
(Non-metal polyatomic ion)
Example #1: Sodium Hydroxide
Sodium Ion = Na+
Hydroxide Ion = (OH)-
Na+ (OH)-
*Need to balance the charges
Na+ : (OH)- (ions)
+1 : -1 (charges = balanced)
Na1(OH)1
NaOH
Like all ionic compounds, sodium hydroxide is neutral

8. Example #2 Calcium Hydroxide
(Metal ion) +
(Non-metal polyatomic ion)
Example #2 Calcium Hydroxide
Calcium Ion = Ca2+
Hydroxide Ion = (OH)-
Ca2+ (OH)-
*Need to balance the charges
Ca2+ : OH- (ions)
2+ : 1- (charges)
x1 : x2 (multiply to balance charges)
2+ : 2- (charges are balanced)
1 : (ratio)
Ca1(OH)2
CaOH2
Ca(OH)2

9. What do Ionic Compounds look like?

10. Ionic Compounds... They tend to be solid at room temperature
They exist as crystal lattices
Organized in a repeating array
Physical properties:
Hard
Brittle (will shatter with hit with enough force)
High melting and boiling points
Conduct electricity when dissolved in water

11. Example #1: Sodium Chloride

12. Example #2: Sodium Hydroxide

13. ACTIVITY
Look at the products and identify chemical formula of the ionic compounds listed

14. TOOTHPASTE
Sodium Fluoride
Ions = Na+ and F-
Ionic Compound = NaF

15. SUNBLOCK Zinc Oxide Ions = Zn2+ and O2-
Ionic Compound = ZnO - don’t forget to simplify!

16. BAKING SODA Sodium Bicarbonate Ions = Na+ and (HCO3)-
Ionic Compound = NaHCO3

17. ANTACIDS (for heartburn)
Aluminum Hydroxide
Ions = Al3+ and OH-
Ionic Compound = Al(OH)3
Magnesium Carbonate
Ions = Mg2+ and (CO3)2-
Ionic Compound = MgCO3 - don’t forget to simplify!

18. TUMS (another antacid)
Calcium Carbonate
Ions = Ca2+ and (CO3)2-
Ionic Compound = CaCO3 - don’t forget to simplify

19. Please work with a partner on the practice questions on your handout
Additional homework questions:
pg #9 & 10
pg Review Questions #1-8