1. Polyatomic Ions and Molecular Nomenclature
Lesson 15
October 25th, 2010

2. Polyatomic Ions
Ions that are composed of one atom are called monatomic ions.
Monatomic Ion- an ion composed of only one atom.
We have only looked at these so far

3. Polyatomic Ions
Polyatomic Ions are ions that are composed of more than one atom. The entire molecule carries a charge to it. - Example
NO3-
SO42-
PO43-

4. Bonding
Ionic Bonding with polyatomic ions occurs in the same manner as it does with standard ionic molecules.
- Use the crossover method
- Be sure that the charge that is crossed over applies to the whole polyatomic ion. If the charge is greater than 1, use brackets around the polyatomic ion to indicate the number applies to the whole ion.

5. Example 1
Step 1
Na + NO3-
Step 2
Na NO3
Step 3
Step 4
NaNO3

6. Example 2
Step 1
Mg + NO3-
Step 2
Mg NO3
Step 3
Step 4
Mg (NO3)2

7. Practice Mg + ClO3- = Na + SiO32- = Fr + HS- = NH4+ + Cl = Li + Cl =
Be + O22- =
Sr + PO43- =
Al + BO33- =
Al + SO42- =
Na + OH- =

8. Naming Ionic Polyatomic compounds: IUPAC
Multivalent: Metal (charge) polyatomic ion
Monovalent: Metal polyatomic ion
Tertiary ionic compounds are comprised of a metal ion and a polyatomic ion. Write the polyatomic ions in the same way as monatomic ions.

9. Examples NaOH = Cu(ClO4)2 = Tin (IV) chlorate =
sodium hydroxide (NOT MULTIVALENT)
Cu(ClO4)2 =
copper (II) perchlorate
Tin (IV) chlorate =
Sn (ClO3)4

10. Practice Cr3+ CO32- Chromium (III) Carbonate Copper (I) hydroxide =
= Cu+ OH-
= CuOH
Aluminum sulfate =
Al3+ SO43-
= AlSO4
Ended here
CrCO3 =
Cr2+ CO32-
=Chromium (II) Carbonate
Cr2(CO3)3 =
Cr3+ CO32-
Chromium (III) Carbonate

11. Naming Binary Molecular Compounds: IUPAC
Write down the name of the first element. If there is more than one atom of this element attach a Greek prefix. (if there is only one atom do not attach the prefix)
Attach a Greek prefix (relating to the number of atoms) to the second elements name and add -ide.

12. Prefixes # of atoms 1 2 3 4 5 6 7 8 9 10 Prefix Mono Di Tri Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca

13. Example:
CO = Carbon monoxide
CO2 = Carbon dioxide

14. Additional Rules
Elements that are commonly bonded to themselves in nature do so to make themselves more stable. These molecules are known as diatomic Molecules. Some common examples include (O2, H2, N2, Br2, Cl2, S8). When we name them they retain their element name without the use of prefixes. Example. O2 is not dioxide. It is just Oxygen gas.

15. Practice HF = Hydrogen monofluoride PBr =Phosphorous monobromide
carbon tetrafluoride = CF4
Silicon dibromide =SiBr2

16. Complete all of the practice Questions
Unit Test On Thursday