1. Chapter 5 Nomenclature

2. History of Naming
When chemistry first came about, there was no general naming system.
Scientists used common names like laughing gas, epsom salt, and milk of magnesia
This became impractical with the discovery of over 4 million chemical compounds
Therefore scientists developed a standardized system known as nomenclature

3. Naming Binary Compounds
Binary compounds are composed of two elements
There are two classes
Compounds containing a metal & non-metal
Compounds containing two non-metals

4. Naming Binary Ionic Compounds
Metals and non-metals combine to form compounds that contain ions (NaCl)
The metal loses 1 or more electrons to become a cation
The non-metal gains 1 or more electrons to became an anion
These are known as binary ionic compounds (ionic compounds for short)

5. Naming Binary Ionic Compounds
There two types of binary ionic compounds
Type I: The metal present only forms one type of cation (Group IA, 2A, Al)
Type II: The metal can form two or more cations that have different charges (mostly transition metals like chromium, copper, etc)

6. Naming Type I Binary Ionic Compounds
The rules are as follows
The cation is named first and the anion second.
A simple cation takes its name from the name of the element.
A simple anion takes the root name of the element and adds –ide to the end

7. Example 1 Name the following: NaCl
Rule 2: Name of cation is name of element: Sodium
Rule 3: Name of anion is element root with –ide: chloride
Rule 1: Cation first, anion second: Sodium Chloride

8. Example 2 Name the following: AlCl3
Rule 2: Name of cation is name of element
Rule 3: Name of anion is element root plus –ide:
Rule 1: Cation first, anion second

9. Now you try Name the following MgI2 CaS
Now we will try a few examples…

10. Naming Type II Binary Ionic Compounds
There are many metals that can form more than one type of cation
Lead can form Pb2+ or Pb4+
Iron can form Fe2+ or Fe3+
Gold can form Au+ or Au3+

11. Naming Type II Binary Ionic Compounds
Take AuCl vs. AuCl3
If we named this using the rules for Type I compounds, Gold chloride, we wouldn’t know which formula the name was referring to
Chemists have solved this problem by using Roman Numerals to indicate the charge on a cation

12. Naming Type II Binary Ionic Compounds
Consider FeCl2
Fe can form Fe2+ or Fe3+
Compounds containing ions must have a net charge of zero
Fe (?) Cl (-1 x 2 = -2)
Fe must 2+
We name this compound Iron(II) chloride
Note: The Roman Numerals indicate the charge, NOT the number of atoms present

13. Naming Type II Binary Ionic Compounds
The rules are as follows
Cation is named using element name
Charge is indicated by a Roman Numeral after the cation name
Anion is named using element root name and adding –ide

14. Example 1 Name the following: CuCl
We know that chlorine always forms -1 anions
Compounds containing ions must have a net charge of zero
Therefore copper must have a +1 charge
Name: Copper(I) chloride

15. Example 2 Name the following Fe2O3
We know that oxygen always forms -2 anions, providing a total charge of -6 (-2 x 3)
Compound must have a net charge of 0
Therefore iron must contribute +6 worth of charge
There are two iron atoms present, each having a charge of +3
Name: Iron(III) oxide

16. Now you try
PbCl4
MnO2
Now we will try a few examples…

17. Naming Binary Compounds that Contain Only Non-metals (Type III)
Type III compounds only contain non-metals
These are known as non-ionic or covalent compounds

18. Naming Type III Binary Compounds
The rules are as follows
The 1st element in the formula is named first. The full element name is used.
The 2nd element in the formula is named as if it were an anion (-ide ending)
Prefixes are used to denote the number of atoms present
The prefix mono- is never used for naming the first element

19. Prefixes
one mono two di three tri four tetra five penta six hexa seven hepta eight octa

20. Example 1 Name the following BF3 Rule 1: Name the first element: boron
Rule 2: Name the second element like an anion: fluoride
Rule 3 & 4: Use prefixes for number of atoms
1 boron atom (don’t use mono): boron
3 fluorine atoms: trifluoride
Name: boron trifluoride
*Note: When the 2nd element is oxygen, we drop the a or o from the end of the prefix to avoid strange pronunciation

21. Example 2 Name the following N2O5 Rule 1: Nitrogen Rule 2: oxide
2 nitrogen: dinitrogen
5 oxygen: pentoxide
Name: dinitrogen pentoxide

22. Now you try
CCl4
IF5
Now we will try a few examples

23. Polyatomic Compounds
Polyatomic Ions are charge entities composed of several atoms bound together
Unfortunately, the names of most polyatomic atoms need to memorized

24. Oxyanions
Oxyanions contain an atom of a given element and different numbers of oxygen atoms
Example SO4-2

25. Oxyanions Per- -ate SO5-2 Persulfate PO5-3 Perphosphate NO4-1
Pernitrate
ClO4-1
Perchlorate
-ate
SO4-2
Sulfate
PO4-3
Phosphate
NO3-1
Nitrate
ClO3-1
Chlorate
-ite
SO3-2
Sulfite
PO3-3
Phosphite
NO2-1
Nitrite
ClO2-1
Chlorite
Hypo- -ite
SO2-2
Hyposulfite
PO2-3
Hypophosphite
NO-1
hyponitrite
ClO-1
Hypochlorite
-ide
S-2
Sulfide
P-3
Phosphide
N-3
Nitride
Cl-1
Chloride

26. Some other common polyatomic ions
NH4+ Ammonium
OH- Hydroxide
CN- Cyanide
CO3-2 Carbonate

27. Naming using polyatomic ions
Following typical naming rules
Cation named first, anion named second
Name of cation is element name
Name of anion is anion name
If a metal is present that is multivalent, we need to use Roman Numerals to indicate charge

28. Example 1 Na2SO4 Name of cation is name of element: Sodium
Name of anion is anion name: sulfate
We know the charge on sodium, so we don’t need Roman numerals
Name: Sodium sulfate

29. Example 2 Fe(NO3)3 Name of cation is name of element: Iron
Name of anion is anion name: nitrate
Need to calculate charge on copper: +3
Name: Copper (III) nitrate

30. You try
Mn(OH)2
Na2SO3

31. Naming Acids
When dissolved in water, certain compounds produce H+ ions
We call these compounds acids
Acids can be viewed as a compound with one or more H+ ions and an anion
Rules for naming depend on whether anion contains oxygen

32. Naming Acid Rules
Does not contain oxygen: acid is named with the prefix hydro- and the suffix –ic
Example: HCl Hydrochloric acid
2. Does contain oxygen: acid is named with the root name of the central element of the anion and a suffix
a. When the anion name contain –ate, the suffix –ic is used
i.e. H2SO4 SO4 is sulfate sulfuric acid
b. When the anion name contains –ite, the suffix –ous is used
i.e. H2SO3 SO3 is sulfite sulfurous acid

33. Example 1
HBr
Does not contain oxygen
Hydrobromic acid

34. Example 2
HNO3
Contains oxygen
NO3 is nitrate
Nitric acid

35. You try HI
H3PO3