1. QOTD What do you call a negatively charged atom?
What do you call a positively charged atom?
Do you think there is a way to name polyatomic ions? Why or why not?
List 4 polyatomic ions. What does poly mean?

2. Compounds & Nomenclature
Polyatomic Ions
Compounds
&
Nomenclature

3. Objectives Define a polyatomic ion
Name compounds containing a polyatomic ion.
Given the name of a compound containing a polyatomic ion, write its formula.

4. Define a polyatomic ion
Polyatomic Ion: An ion (either positively or negatively charged) composed of two or more atoms.

5. Is it possible to predict charges?
Based on covalent bonding
Charges of polyatomic ions are based on overall stability
Not as predictable as monatomic ions
These will have to be memorized
However, this becomes easy with practice

6. Common Examples
HCO32- Bicarbonate Ion PO43- Phosphate Ion NH4+ Ammonium Ion NO3- Nitrate Ion

7. Name compounds containing a polyatomic ion
Example: NaNO3
If the compound contains a metal cation, the name of the metal comes first.

8. Name compounds containing a polyatomic ion
Example: NaNO3
If the compound contains a metal cation, the name of the metal comes first.
Sodium

9. Name compounds containing a polyatomic ion Example: NaNO3 2
Name compounds containing a polyatomic ion Example: NaNO3 2. The second part of the name is just the name of the polyatomic ion Sodium

10. Name compounds containing a polyatomic ion Example: NaNO3 2
Name compounds containing a polyatomic ion Example: NaNO3 2. The second part of the name is just the name of the polyatomic ion Sodium Nitrate

11. What if the Polyatomic Ion comes first?
NH4+ (Ammonium ion) is a positive ion while still being polyatomic If you are using a polyatomic cation you just use the ion’s name, and it will be written first NH4Cl

12. What if more than one Polyatomic Ion is needed?
Compounds must be neutral!
If > 1 polyatomic ion is needed in a formula, it will be put in parentheses before the subscript
When writing its name, it will just remain the name of the polyatomic ion
Al2 (SO4)3

13. Given the name of a compound containing a polyatomic ion, write its formula. Example: Potassium Carbonate 1. Determine atomic symbols and charges

14. Given the name of a compound containing a polyatomic ion, write its formula. Example: Potassium Carbonate 1. Determine atomic symbols and charges K+ CO32-

15. Given the name of a compound containing a polyatomic ion, write its formula. Example: Potassium Carbonate 2. Determine number of each ion to balance charges K+ CO32-

16. Given the name of a compound containing a polyatomic ion, write its formula. Example: Potassium Carbonate 2. Determine number of each ion to balance charges 2K+ 1CO32-

17. Given the name of a compound containing a polyatomic ion, write its formula. Example: Potassium Carbonate 3. Using symbols for both ions and proper subscripts, write the formula K2CO3

18. Practice Examples 1.
BeSO3 2.
NaC2H3O2 3.
Ca(NO3)2 4.
Aluminum Nitrite 5.
Iron (II) Hydroxide 6.
Ammonium Phosphate

19. NEW SEATING! CHECK THE CHART! QOTD Name/Write the Formula1.
MgSO3 2.
NaF 3. OH 4.
Aluminum Nitrate 5.
Iron (III) Phosphate 6.
Ammonium Hydroxide

20. Happy Thanksgiving Break!