1. Formulas & Nomenclature
Chapter 4
WHS Chemistry

2. Na Cl Do you know what sodium chloride is?
Do you know what symbols are involved in expressing sodium chloride? Na Cl

3. MgS CaO LiBr Magnesium sulfide Calcium oxide Lithium bromide
Try identifying what elements and symbols are involved in the compounds.
MgS
Magnesium sulfide
CaO
Calcium oxide
LiBr
Lithium bromide
What does each begin with? Where is it on PT?
What does each end with? What suffix does each name use? Where is it on PT?

4. Start with simple naming—pay attention to where these elements are on the periodic table!
The cation is almost always listed first in the formula & named first.
The cation is named using the element name.
The anion is almost always listed last in the formula & named last using –ide ending.

5. Let’s try some (ignore the little subscripts for now)
Compound
name
CsF
AlCl3
MgI2
Rb2O
SrI2
K2S
cesium fluoride
aluminum chloride
magnesium iodide
rubidium oxide
strontium iodide
potassium sulfide

6. To put the formulas together correctly, we need to know some basics about the typical charges of the elements.
It is also important to remember that as we put these together, we must charge balance!
Try a few on your paper.

7. Notice that some metals have several charges possible.
…look on your periodic table, where are most of these located?
Try putting some of these with Cl-
Fe2+
Fe3+
Ni2+
Ni3+
Cu+
Cu2+
Sn2+
Sn4+
Hg22+
Hg2+
Pb2+
Pb4+

8. copper ( ) chloride mercury ( ) oxide iron ( ) oxide
Compound
Decide which charge is used
name
CuCl
HgO
Fe2O3
MnO2
PbCl4
Ni2S3
copper ( ) chloride
mercury ( ) oxide
iron ( ) oxide
manganese ( ) oxide
lead ( ) chloride
nickel ( ) sulfide

9. What do the Roman numerals tell us?
iron (III) sulfide
lead (II) nitride

10. calcium bromide magnesium oxide silver nitride tin ( ) chloride
Compound
Do we need a Roman numeral?
name
CaBr2
MgO
Ag3N
SnCl2
CuF2
K3P
Zn3N2
HgO
calcium bromide
magnesium oxide
silver nitride
tin ( ) chloride
copper ( ) fluoride
potassium phosphide
zinc nitride
mercury ( ) oxide

11. NO3- SO42- Polyatomic Ions What is different about these?
What type of bond is likely holding these together?
How might they act if a Mg2+ ion came along?

12. barium nitrite iron ( ) hydroxide potassium nitrate sodium sulfate
Compound
Show the polyatomic ion
name
Ba(NO2)2
Al2(CO3)3
Fe(OH)3
KNO3
(NH4)3PO4
(NH4)2SO4
NaSO4
K3PO4
barium nitrite
aluminum carbonate
iron ( ) hydroxide
potassium nitrate
ammonium phosphate
ammonium sulfate
sodium sulfate
potassium phosphate

13. Cation Formula Name Ca2+ NO2- K+ SO4-2 Cu2+ OH- Fe2+ CO3-2 Co3+ NO3-
Polyatomic ion
Formula
Name
Ca2+
NO2- K+
SO4-2
Cu2+
OH-
Fe2+
CO3-2
Co3+
NO3-
Ag+
NH4+
C2O4-2
Sn4+
PO4-3