chemistry ionic compounds and naming.ppt

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 Ba
2+
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 Ba
2+
/ Cl

Cl

3. Write the number of ions needed as
subscripts

BaCl
2

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 BaF
2
-

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: Al
3O
2
•SWAP: Al
2O
3
•REDUCE: 2 and 3 are lowest integers, so
leave alone
•The Final Formula is Al
2O
3
Also called “Cris
—
Cross”!

11. Another example
•Magnesium Oxide
•Mg is +2
•Oxide is -2
•Mg
+2
, O
-2
•DROP: Mg
2O
2
•SWAP: Mg
2O
2
•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
+
,

S
2-
a) NaS b) Na
2S c) NaS
2
2. Al
3+
, Cl
-
a) AlCl
3
b) AlCl c) Al
3
Cl
3. Mg
2+
, N
3-
a) MgN b) Mg
2N
3 c) Mg
3N
2

13. Solution
1. Na
+
,

S
2-
b) Na
2
S
2. Al
3+
, Cl
-
a) AlCl
3
3. Mg
2+
, N
3-
c) Mg
3
N
2

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

15. Naming Binary Ionic Compounds
Examples:
NaCl
ZnI
2
Al
2
O
3
•sodium chloride
•zinc iodide
•aluminum oxide

16. Learning Check
Complete the names of the following binary
compounds:
Na
3N sodium ________________
KBr potassium________________
Al
2O
3 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
+
,

Cu
2+
Fe
2+
, Fe
3+
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
FeCl
3
(Fe
3+
)

iron (III) chloride
CuCl (Cu
+
) copper (I) chloride
SnF
4
(Sn
4+
)

tin (IV) fluoride
PbCl
2
(Pb
2+
)lead (II) chloride
Fe
2S
3 (Fe
3+
)iron (III) sulfide

19. Learning Check
Complete the names of the following binary compounds
with variable metal ions:
FeBr
2 iron (_____) bromide
CuCl copper (_____) chloride
SnO
2 _____(_____ ) ____________
Fe
2
O
3
________________________
Hg
2S ________________________

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

21. Formulas and names
•Nitrate = NO
3
-

•Sulfate = SO
4
-2
•Silver nitrate
–Ag
+
NO
3
-

–AgNO
3
•Copper (I) Sulfate
–Cu
+
SO
4
-2
–Cu
2SO
4

22. More Polyatomics
•Lead (IV) Phosphate
–Pb
+4
PO
4
-3
–Pb
3
(PO
4
)
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
+
, PO
4
-3

a) NaPO
4 b) Na
2
PO
4 c) Na
3
PO
4
2. Al
3+
, NO
3
-

a) Al(NO
3)
3 b) AlNO
3 c) Al
3
NO
3
3. NH
4
+
, N
3-
a) NH
4N b) NH
4N c) (NH
4)
3N

24. Answers
•1. Na
+
, PO
4
-3
• c) Na
3
PO
4
•2. Al
3+
, NO
3
-

–a) Al(NO
3)
3
• 3. NH
4
+
, N
3-
–c) (NH
4)
3
N

25. Polyatomic Ions you have to know
NAME FORMULA
Acetate C
2
H
3
O
-1
Carbonate CO
3
-2
Chlorate ClO
3
-1
Cyanide CN
-1

Hydroxide OH
-1
Nitrate NO
3
-1
Peroxide O
2
-2
Phosphate PO
4
-3

Sulfate SO
4
-2

Ammonium NH
4
+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:
• NO
3
-
NO
2
-
•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