1. Naming Compounds Writing Formulas
Chapter 5
Naming Compounds
Writing Formulas

2. Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
Ionic - a cation and an anion.
To write the names just name the two ions.
Easy with Representative elements.
Group A
NaCl = Na+ Cl- = sodium chloride
MgBr2 = Mg+2 Br- = magnesium bromide

3. Naming Binary Ionic Compounds
The problem comes with the transition metals.
Need to figure out their charges.
The compound must be neutral.
same number of + and – charges.
Use the anion to determine the charge on the positive ion.

4. Naming Binary Ionic Compounds
Write the name of CuO
Need the charge of Cu
O is -2
copper must be +2
Copper (II) chloride
Name CoCl3
Cl is -1 and there are three of them = -3
Co must be +3 Cobalt (III) chloride

5. Naming Binary Ionic Compounds
Write the name of Cu2S.
Since S is -2, the Cu2 must be +2, so each one is +1.
copper (I) sulfide
Fe2O3
Each O is x -2 = -6
2 Fe must = +6, so each is +3.
iron (III) oxide

6. Naming Binary Ionic Compounds
Write the names of the following
KCl
Na3N
CrN
Sc3P2
PbO
PbO2
Na2Se

7. Ternary Ionic Compounds
Will have polyatomic ions
At least three elements
Just write the name of the element using the front of the periodic table and the polyatomic ion using the chart on the back of the table.
Examples of naming ternary ionic compounds:
NaNO3 = sodium nitrate
(NH4)2O = ammonium oxide

8. Ternary Ionic Compounds name these:
LiCN
Fe(OH)3
(NH4)2CO3
NiPO4
CaSO4
CuSO3

9. Writing Formulas The charges have to add up to zero.
Get charges for the 2 parts.
Cations from location on p. table.
Anions from p. table or polyatomic.
Balance the charges by putting in subscripts (small #’s on bottom right).
Put polyatomic ions in parenthesis before you give them subscripts.

10. Writing Formulas CaCl2 Write the formula for calcium chloride.
Calcium is Ca+2
Chloride is Cl-1
Ca+2 Cl-1 would have a +1 charge.
Need another Cl-1
Ca+2 Cl2-1
CaCl2

11. Write the formulas for these
Lithium sulfide
tin (II) oxide
tin (IV) oxide
Magnesium fluoride
Copper (II) sulfate
Iron (III) phosphide
gallium nitrate
Iron (III) sulfide

12. Write the formulas for these
Ammonium chloride
ammonium sulfide
barium nitrate

13. Things to look for
If cations have (roman numeral), the number is their charge.
If anions end in -ide they are probably off the periodic table (Monoatomic)
Exceptions (Hydroxide (OH); Cyanide (CN) are polyatomic.
If anion ends in -ate or -ite it is polyatomic.

14. Writing names and Formulas
Molecular Compounds
Writing names and Formulas

15. Molecular compounds made of just nonmetals
smallest piece is a molecule
can’t be held together because of opposite charges
can’t use charges to figure out how many of each atom

16. Easier Ionic compounds use charges to determine how many of each.
Have to figure out charges.
Have to figure out numbers.
Molecular compounds name tells you the kind of atoms.
Uses prefixes to tell you the number

17. Prefixes 1 mono- 2 di- 6 hexa- 3 tri- 7 hepta- 8 octa- 4 tetra-
5 penta-
6 hexa-
7 hepta-
8 octa-
9 nona-
10 deca-

18. Prefixes Prefix name Prefix name -ide
To write the name write two words
Prefix
name
Prefix
name
-ide

19. Prefixes Prefix name Prefix name -ide
To write the name write two words
One exception is we don’t write mono- if there is only one of the first element.
Prefix
name
Prefix
name
-ide

20. Prefixes Prefix name Prefix name -ide
To write the name write two words
One exception is we don’t write mono- if there is only one of the first element.
No double vowels when writing names (oa oo)
Prefix
name
Prefix
name
-ide

21. Name These Ex. CO carbon monoxide CO2 carbon dioxide
P2O5 diphosphorus pentoxide
Name These
N2O
NO2
Cl2O7
CBr4
BaCl2

22. Write formulas for these
diphosphorus pentoxide
tetraiodide nonoxide
sulfur hexaflouride
nitrogen trioxide
Carbon tetrahydride
phosphorus trifluoride
aluminum chloride

23. Writing names and Formulas
Acids
Writing names and Formulas

24. Acids Compounds that give off hydrogen ions when dissolved in water.
Must have H in them.
will always be some H next to an anion.
The anion determines the name.

25. Naming acids
If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid
HCl - hydrogen ion and chloride ion
hydrochloric acid
H2S hydrogen ion and sulfide ion
hydrosulfuric acid

26. Naming Acids If the anion has oxygen in it it ends in -ate or -ite
change the suffix -ate to -ic acid
HNO3 Hydrogen and nitrate ions
Nitric acid
change the suffix -ite to -ous acid
HNO2 Hydrogen and nitrite ions
Nitrous acid

27. Name these HF
H3P
H2SO4
H2SO3
HCN
H2CrO4

28. Writing Acid Formulas/Naming
Hydrogen will always be first
name will tell you the anion
make the charges cancel out
Starts with hydro- if no oxygen in the acid, -ide ending becomes –ic
Ex. HCl = hydochloric acid
no hydro, -ate ending from polyatomic ion becomes -ic, H2SO4 = sulfuric acid
-ite ending becomes –ous, H2SO3 = sulfurous acid

29. Write formulas for these
hydroiodic acid
acetic acid
carbonic acid
phosphorous acid
hydrobromic acid