2. Compound Review Elements naturally exist in compounds
2 or more chemically combined elements
They form compounds to be more stable = have full outer energy levels of electrons
8 for every element but H and He
Two main types of bonds are ionic and covalent
Ionic = between a metal and nonmetal. The metal transfers electrons to the nonmetal.
Covalent = between nonmetals. Electrons are shared.

3. Ionic Compounds An ionic compound is made of charged ions
Cation = positively charged metal ion
Positive because metals lose electrons
Anion = negatively charged nonmetal ion
Negative because nonmetals gain electrons
Although an ionic compound is made up of charged ions, the overall charge of the compound must be zero
Aka– the amount of (+) charge must equal the amount of (-) charge

4. How to determine the Chemical Formula for an Ionic Compound
Name  Formula
Write down the ions of each element with charge.
(aka the symbol with its oxidation #)
Determine the # of each ion it takes to make a compound with no charge.
(aka “crisscross applesauce” the charges)
Write down the formula using subscripts to show how many of each ion it took.
Reduce/simplify. (if needed)

5. Example: What is the formula for the compound that forms between magnesium and phosphorous?
Mg+2
P-3
Mg3P2
3(+2) + 2(-3) = 0

6. Practice Time! Write the chemical formulas if the elements below formed compounds.
Aluminum and Chlorine
Lithium and Nitrogen
Magnesium and Iodine
Calcium and Oxygen
Sodium and Sulfur
AlCl3
Li3N
MgI2
CaO
Na2S

7. How to Name Ionic Compounds Formula  Name
Write the name of the first element. (the metal)
Write the name of the second element (the nonmetal) with an –ide ending.
Example: CaS
Calcium sulfide

8. Practice Time! Write the name of the compounds based on the chemical formulas below.
Be3N2
Na2O
K3P
AlN
MgCl2
Beryllium Nitride
Sodium Oxide
Potassium Phosphide
Aluminum Nitride
Magnesium Chloride

9. Pause and Practice

10. Exception #1: Polyatomic Ions
Polyatomic Ions = a positively or negatively charged, covalently bonded, group of atoms
Common ones to know:
Ammonium - NH4+1 Sulfate - SO4-2
Nitrate - NO3-1 Carbonate - CO3-2
Hydroxide - OH-1 Acetate - C2H3O2-1
Phosphate - PO4-3 Chlorate - ClO3-1

11. How to Name Ionic Compounds Formula  Name
Write the name of the first element (the metal)
Exception #1: if polyatomic ion, use special name
Write the name of the second element (the nonmetal) with an –ide ending
Exception #1: if polyatomic ion, use special name. No –ide ending.
Examples:
Na3PO4
MgSO4
NH4Cl
Sodium phosphate
Magnesium sulfate
Ammonium chloride

12. Practice Time! With Exception #1 Write the name of the compounds based on the chemical formulas below.
NaNO3
CaSO4
(NH4)2O
Mg3(PO4)2
NH4NO3
Sodium Nitrate
Calcium Sulfate
Ammonium Oxide
Magnesium Phosphate
Ammonium Nitrate

13. How to determine the Formula for an Ionic Compound w/ polyatomic ions
Name  Formula
Write down the ions of each element with charge (aka the symbol with its oxidation #) (just keep polyatomic ion in parentheses)
Determine the # of each ion it takes to make a compound with no charge
(aka “crisscross applesauce” the charges) (keep subscripts outside of parentheses and don’t change ANYTHING inside)
Write down the formula using subscripts to show how many of each ion it took
Reduce/simplify (if needed)
Calcium phosphate
Ca+2
(PO4) -3
Ca3(PO4)2

14. Practice Time! With Exception #1 Determine the chemical formulas for the following chemical compounds.
Barium sulfate
Aluminum carbonate
Calcium nitrate
Sodium acetate
Potassium phosphate
BaSO4
Al2(CO3)3
Ca(NO3)2
NaC2H3O2
K3PO4

15. Pause and Practice

16. Transition Metals copper (I)  copper (II)  Cu+1 Cu+2
Transition metals “transition” because they can form many different ions
Ex. Sodium is always Na+1 because it is in group 1 and group 1 metals have one valence electron  therefore they lose 1 e- to be stable
Iron as a transition metal can be Fe+2 or Fe+3
Because you can’t determine the oxidation number from the periodic table, a Roman Numeral is used to show it
copper (I) 
copper (II) 
Cu+1
Cu+2

17. Exception #2: Transition Metals
How to Name Ionic Compounds (formula  name)
Write the name of the first element (the metal)
Exception #2: if a transition metal, include a Roman numeral to indicate the charge of the metal
Write the name of the second element (the nonmetal) with an –ide ending
Examples:
CuCl
CuCl2
Copper (I) Chloride
Copper (II) Chloride

18. Determining the Roman Numeral for Transition Metals
Option 1: Reverse crisscross
Option 2: Use visuals or math to determine what charge of cation must be for overall charge to be zero.
 Regardless of option you prefer, ALWAYS double check!!
Ex. #1:
Sn3(PO4)4
Option 2:
Option 1: -3
Sn?
(PO4)-3 ?
Sn3(PO4)4 -3 ?
Tin (IV) phosphate ? -3
Tin (IV) phosphate
3(?) = +12 -3 +4
4(-3) = -12

19. Determining the Roman Numeral for Transition Metals
Option 1: Reverse crisscross
Option 2: Use visuals or math to determine what charge of cation must be for overall charge to be zero.
 Regardless of option you prefer, ALWAYS double check!!
Ex. #2:
FeSO4
Option 2:
Option 1: ? -2
Fe?
(SO4)-2
FeSO4
1(?) = +2
1(-2) = -2
Since the 2 isn’t there, it must have reduced. These are harder! What would it be then? +2
Iron (II) sulfate
Iron (II) sulfate

20. Practice Time! With Exception #2 Write the name of the compounds based on the chemical formulas below.
FeCl3
CrO
Mn2O7
CrN
Ag2S
Iron (III) Chloride
Chromium (II) Oxide
Manganese (VII) Oxide
Chromium (III) Nitride
Silver (I) Sulfide

21. How to determine the Formula for an Ionic Compound w/ transition metals (name  formula)
Write down the ions of each element with charge (aka the symbol with its oxidation #) (The transition metals charge will be given by the use of Roman Numerals.)
Iron (II) Oxide
Determine the # of each ion it takes to make a compound with no charge (aka “crisscross applesauce”)
Write down the formula using subscripts to show how many of each ion it took
Fe2O2
Reduce/simplify (if needed)
FeO
Fe+2
O-2

22. Practice Time! With Exception #2 Determine the chemical formulas for the compounds below based on the names.
Copper (II) sulfide
Iron (I) nitride
Manganese (IV) oxide
Chromium (VI) sulfide
Titanium (IV) bromide
CuS
Fe3N
MnO2
CrS3
TiBr4

23. Pause and Practice

24. SUMMARY: Steps for Naming Ionic Compounds (formula  name)
Name the metal (cation)
Exception #1 = If polyatomic ion, use its special name
Exception #2 = If a transition metal, use a Roman Numeral to indicate the charge of the metal
Name the nonmetal (anion) with –ide ending
Exception #1 = If polyatomic ion, use its special name, no -ide

25. Practice Time! Formula  Name
MgCl2
(NH4)3PO4
Ni(OH)2
Magnesium chloride
Ammonium phosphate
Nickel (II) hydroxide

26. SUMMARY: Steps for Writing Chemical Formulas for Ionic Compounds
(name  formula)
Write down the ions with charge
Crisscross the charges to determine subscripts
(aka “criss cross applesauce”) (keep subscripts outside of parentheses and don’t change ANYTHING inside)
Rewrite with subscripts
Reduce/simplify (if needed)

27. Practice Time! Name  Formula
NaCl
Sodium chloride
Aluminum hydroxide
Iron (III) oxide
Al(OH)3
Fe2O3

28. Helpful Hints for Ionic Compounds
When determining the Roman numeral for a transitional metal, try to reverse crisscross first.
If the subscript doesn’t match the charge of the known nonmetal, then it must have been simplified.
When it doesn’t match, do a little trial and error. Double check your work by going the opposite way (determining formula from name) and see if your results match what you started with.
Always put parentheses around polyatomic ions so you remember to “protect” them.
You CANNOT change the subscripts of the polyatomic ions, so using parentheses will help you to remember that!

29. Pause and Practice