1. aka Naming Compounds Unit 3
Nomenclature
aka Naming Compounds
Unit 3

2. Binary Ionic Compounds
A two-element compound consisting of a cation and an anion.
We will look at two different kinds of binary ionic compounds.

3. Type I Binary Ionic Compounds
The metal present forms only one type of cation.
Group 1 and 2 metals are always type I.
Na  𝑁𝑎 +
Cs  𝐶𝑠 +
Ca  𝐶𝑎 2+
Al  𝐴𝑙 3+

4. Rules for Naming Type I Ionic Compounds
The cation is always named first & the anion second
A simple cation (obtained from a single atom) takes its name from the name of the element.
Ex. 𝑁𝑎 + is called sodium in the names of compounds containing this ion.

5. Write the name for the compound by combining the names of ions
A simple anion (obtained from a single atom) is named by taking the first part of the element name (root) and adding –ide.
Ex. 𝐶𝑙 − ion is called chloride.
Write the name for the compound by combining the names of ions

6. Examples: Type I Compounds
Ions Present
Name
NaCl
𝑁𝑎 + , 𝐶𝑙 −
Sodium Chloride KI
𝐾 + , 𝐼 −
Potassium Iodide
CaS
𝐶𝑎 2+ , 𝑆 2−
Calcium Sulfide
CsBr
𝐶𝑠 + , 𝐵𝑟 −
Cesium Bromide
MgO
𝑀𝑔 2+ , 𝑂 2−
Magnesium Oxide

7. Practice Give the formulas for the following binary compounds.
sodium fluoride
NaF
lithium sulfide
𝐿𝑖 2 𝑆
calcium bromide
Ca 𝐵𝑟 2

8. Practice Beryllium Fluoride Aluminum bromide
Write the names for the following binary compounds.
BeF2
Beryllium Fluoride
NaI
Sodium iodide
AlBr3
Aluminum bromide

9. Practice Radium nitride Strontium Oxide
Write the names for the following binary compounds.
Ra3N2
Radium nitride
K2S
Potassium sulfide
SrO
Strontium Oxide

10. Type II Binary Compounds
The metal present can form two or more cations that have different charges.
Follow the same rules for Type I compounds but include a Roman numeral
The Roman numeral tells the charge on the ion, not the number of ions present in the compound.
Metals that form only one cation do not need to be identified by a Roman numeral.

11. Ex: Type II Ionic Compounds
CuCl
Cu = Cation (plus 1 charge)
Cl = Anion (negative 1 charge)
Name: Copper chloride

12. Ex: Type II Ionic Compounds
HgO
Hg = Cation (plus 2 charge)
O = Anion (negative 2 charge)
Name: Mercury (II) oxide

13. Rules for Naming: Type III Binary Compounds (Contain Only Nonmetals)
The first element in the formula is named first, and the full element name is used.
The second element is named as though it were an anion
Prefixes are used to denote the numbers of atoms present.
These prefixes are given in Table 4.3
The prefix mono- is never used for naming the first element.
Ex. CO is called carbon monoxide, not monocarbon monoxide

14. Prefixes in Covalent Compounds
Number of Atoms
Prefix 1
mono- 6
hexa- 2
di- 7
hepta- 3
tri- 8
octa- 4
tetra- 9
nona- 5
penta- 10
deca-

15. Naming Compounds That Contain Ployatomic Ions
You must memorize the names of the polyatomic ions
A polyatomic ion consisting of two or more atoms bound together.
Oxyanion – A polyatomic ion containing at least one oxygen atom and one or more atoms of at least one other element.

16. Naming Acids

17. An acid is defined as a substance that gives off a hydrogen ion (H+) in water. Therefore all acids are made up of a hydrogen cation and either a monatomic or polyatomic anion.
Acid names are based on the anion ending.

18. Rules for Naming Acids
If the anion does not contain oxygen, the acid is named with the prefix hydro- and the suffix –ic attached to the root name for the element.
Example: Acid – HCl
Anion – Cl –
Name – hydrochloric acid

19. Anion ending
_____- ide
Acid Name
hydro-_____-ic + acid

20. Example
H+ + Br- (bromide) 
HBr or
hydrobromic acid

21. Rules for Naming Acids
When the anion contains oxygen, the acid name is formed from the root name of the central element of the of the anion or the anion name with a suffix of –ic or –ous.
When the anion name ends in –ate, the suffix –ic is used.
For example: Acid H2SO4
Anion: sulfate
Name: Sulfuric Acid

22. Anion ending
_______- ate
Acid Name
__________- ic + acid

23. Example
H+ + SO42- (sulfate) 
H2SO4 or
sulfuric acid

24. Rules for Naming Acids
When the anion name ends in –ite, the suffix –ous is used in the acid name
For example: Acid – H2SO3
Anion: sulfite
Name: Sulfurous acid

25. Anion ending
________- ite
Acid Name
_________- ous + acid

26. Example
H+ + NO2- (nitrite) 
HNO2 or
nitrous acid