chem ionic comp and naming

1. IONIC COMPOUNDS
Naming and Formula Writing

2. Monatomic Ions

3. Predicting Charges on Monatomic Ions
KNOW THESE !!!!
+1 +2 -3 -2 -1 0
Cd+2

4. Naming Positive Ions
• Before you name an Ion you have to
know the charge
• Group 1 = always +1
• Group 2 = always +2
• Aluminum = always +3
• Zinc and Cadmium = always +2
• Silver = always +1

5. Naming Positive Ions
• With group 1, 2, Al, Zn, Cd, and Ag you
just give the name of the atom
– Na+
is Sodium
– Mg+2
is Magnesium
– Ag+
is Silver
– Al+3
is Aluminum

6. Naming Negative Ions
• All negative ions have their endings
changed to –ide
• Oxygen becomes oxide
• Fluorine becomes Fluoride
• Nitrogen becomes Nitride
• Chlorine becomes Chloride

7. Formulas of Ionic Compounds
Formulas of ionic compounds are determined
from the charges on the ions
atoms ions
    -
Na 
+ 
F  Na+
F  NaF
   
sodium + fluorine sodium fluoride formula
Charge balance: 1+ 1- = 0







8. Writing a Formula
Write the formula for the ionic compound that will
form between Ba2+
and Cl
To cancel out Ba’s +2, then two -1 Cl’s are needed!
Solution:
1. Balance charge with + and – ions
2. Write the positive ion of metal first, and the
negative ion Ba2+
/ Cl
Cl
3. Write the number of ions needed as
subscripts BaCl2

9. Balancing a formula by math
• Every ionic compound should have a
formula that has a charge that equals
zero
• Barium Fluoride
– Ba+2
F-
– How many F ’s are needed to balance Ba+2
?
– Two
– So, the Formula is BaF2
-

10. Another way – Drop, Swap,
Reduce
• What is the formula for Aluminum Oxide?
• Al is always +3
• Oxide is always -2
• Al+3
, O-2
• DROP: Al3O2
• SWAP: Al2O3
• REDUCE: 2 and 3 are lowest integers, so
leave alone
• The Final Formula is Al2O3
Also called “Cris
—Cross”!

11. Another example
• Magnesium Oxide
• Mg is +2
• Oxide is -2
• Mg+2
, O-2
• DROP: Mg2O2
• SWAP: Mg2O2
• REDUCE: MgO, 2 and 2 divide each other
out
• The Final Formula is MgO

12. Learning Check
Which is the correct formula for the
compounds containing the following ions:
1. Na+
, S2-
a) NaS b) Na2S c) NaS2
2. Al3+
, Cl-
a) AlCl3 b) AlCl c) Al3Cl
3. Mg2+
, N3-
a) MgN b) Mg2N3 c) Mg3N2

13. Solution
1. Na+
, S2-
b) Na2S
2. Al3+
, Cl-
a) AlCl3
3. Mg2+
, N3-
c) Mg3N2

14. Naming Compounds
Binary Ionic Compounds:
1. Cation first (+), then anion (-)
2. Monatomic cation = name of the element
• Ca2+
= calcium ion
3. Monatomic anion = root + -ide
• Cl-
= chloride
• CaCl2 = calcium chloride

15. Naming Binary Ionic Compounds
Examples:
NaCl
ZnI2
Al2O3
• sodium chloride
• zinc iodide
• aluminum oxide

16. Learning Check
Complete the names of the following binary
compounds:
Na3N sodium ________________
KBr potassium ________________
Al2O3 aluminum ________________
MgS ________________________

17. Transition Metals
Elements that can have more than one possible
charge MUST have a Roman Numeral to
indicate the charge on the individual ion
1+ or 2+ 2+ or 3+
Cu+
, Cu2+
Fe2+
, Fe3+
copper (I) ion iron(II) ion
copper (II) ion iron(III) ion
ROMAN
NUMERALS:
I = one
II = two
III = three
IV = four…

18. Names of Variable Ions
These elements REQUIRE Roman Numerals
because they can have more than one possible
charge:
anything except Group 1A, 2A, Ag, Zn, Cd, and Al
(You should already know the charges on these!)
Or another way to say it is:
Transition metals and the metals in groups 4A and
5A (except Ag, Zn, Cd, and Al) require a Roman
Numeral
FeCl3 (Fe3+
) iron (III) chloride
CuCl (Cu+
) copper (I) chloride
SnF4 (Sn4+
) tin (IV) fluoride
PbCl2 (Pb2+
) lead (II) chloride
Fe2S3 (Fe3+
) iron (III) sulfide

19. Learning Check
Complete the names of the following binary compounds
with variable metal ions:
FeBr2 iron (_____) bromide
CuCl copper (_____) chloride
SnO2 _____(_____ ) ____________
Fe2O3 ________________________
Hg2S ________________________

20. Polyatomic Ions
• Some ions are composed of more then
one atom
• These are called polyatomic ions
– Poly = more

21. Formulas and names
• Nitrate = NO3
-
• Sulfate = SO4
-2
• Silver nitrate
– Ag+
NO3
-
– AgNO3
• Copper (I) Sulfate
– Cu+
SO4
-2
– Cu2SO4

22. More Polyatomics
• Lead (IV) Phosphate
– Pb+4
PO4
-3
– Pb3(PO4)4
• Notice: When more then one
Polyatomic is present you surround it
with ()
• Notice: The subscripts on Polyatomic
ions are NEVER changed

23. Learning Check
Write the correct formula for the compounds
containing the following ions:
1. Na+
, PO4
-3
a) NaPO4 b) Na2PO4 c) Na3PO4
2. Al3+
, NO3
-
a) Al(NO3)3 b) AlNO3 c) Al3NO3
3. NH4
+
, N3-
a) NH4N b) NH4N c) (NH4)3N

24. Answers
• 1. Na+
, PO4
-3
• c) Na3PO4
• 2. Al3+
, NO3
-
– a) Al(NO3)3
• 3. NH4
+
, N3-
– c) (NH4)3N

25. Polyatomic Ions you have to know
NAME FORMULA
Acetate C2H3O-1
Carbonate CO3
-2
Chlorate ClO3
-1
Cyanide CN-1
Hydroxide OH-1
Nitrate NO3
-1
Peroxide O2
-2
Phosphate PO4
-3
Sulfate SO4
-2
Ammonium NH4
+1

26. More on Polyatomics
• Most polyatomic ions end in –ate
• The ending –ite means one less oxygen is
present then in the ending –ate
• Example: Nitrate versus Nitrite:
• NO3
-
NO2
-
• NOTICE: Only the number of O’s
changed, not the charge!

27. Properties of Ionic Compounds
• Ionic compounds are:
– also known as salts
– They are usually hard and brittle
– Conduct electricity when molten or
dissolved
– Have very high melting and boiling points
– Most are soluble in water
– Normally composed of at least one metal
and one nonmetal