Ionic Bonding Notes

Notes on ionic bonding.

1. Ionic Compounds
are formed from a metallic
cation, and a non-metallic anion

2. Ionic Bonding
lAnions and cations are held
together by opposite charges.
lIonic compounds are called salts.
lThe bond is formed through the
transfer of electrons.
lElectrons are transferred to achieve
a noble gas configuration. (very
stable)

3. . .
..
..
.
.Na+Cl Na
+
+
.
..
..
.
.Cl. -
Example 1
Na has 1 valence electron because it
is in Group 1
Cl has 7 valence electrons because it
is in Group 17

4. Example 1
Na
+
Cl
-
Na gives his one valence electron to Cl.
Now both atoms are happy. They each
have a stable set-up of electrons like
noble gases. How many do they need in
their valence shell to be stable?

5. Ionic Bonding
lAll the electrons must be
accounted for!
Ca P

6. Ionic Bonding
Ca P
Sometimes atoms can’t satisfy
each other in a one to one ratio

7. Making Formulas
Ca
+2
P
Notice Ca is happy but P still needs
one more electron. So watch what
happens.

8. Ca
+2
P
Ca
Making Formulas

9. Ca
+2
P
-3
Ca
But what about the
2nd Ca?
Making Formulas

10. Ca
+2 P
-3
Ca P
Making Formulas

11. Ca
+2 P
-3
Ca
+2
P
OK, 2nd Ca is Happy but 2nd P is
not now!
Making Formulas

12. Ca
+2
Ca
+2
Ca
Making Formulas
P
-3
P

13. Ca
+2
Ca
+2
Ca
+2
Finally everyone’s
happy!
Making Formulas
P
-3
P
-3

14. Ca
3
P
2
So what’s the formula for this
Compound?
Making Formulas
Now complete your Ionic
Formulas Worksheet.

15. Steps to remember
1)Get charges for the cation and
anion.(Look at the Periodic Table)
Cation always comes first!
2)Put polyatomics in parenthesis.
3)Balance the charges so that they
add up to zero by using
subscripts. (Cross method)

16. Writing Formulas: The Cross-Out
Method
lSteps to Remember:
l1) Get charges for the cation and
anion. Cation always comes first!
l2)Balance the charges so that they
add up to zero by using subscripts.
(cross-out method)

17. Reminder: Get charges from
the Periodic Table
+2
+1
+3-3-2-1

18. Cation? Anion?
Ba
+2
Br
-1
BaBr
2
(The one is understood)
Example: Ba and Br
Now
complete
your ionic
cross-out
worksheet.

19. Polyatomic Ions
lGroups of atoms that stay together
and have a charge.
lFound on p. 7 of your Chemistry
Reference Tables
Name
Charge Formula

20. How Do We Use Polyatomic Ions?
lWhen writing them as either cation
or anion we ...
l... put parenthesis around the ion.
lExample: ammonium becomes
(NH
4
)
+
lSo ammonium chloride would
become (NH
4
)Cl

21. Calcium and nitrate
Cation Anion
Ca
+2
NO
3
-1
Ca(NO
3
)
2
Remember: Polyatomic ion goes in parentheses.
Example with Polyatomic Ions

22. Writing Names
Step 1 – Separate
cation and anion from
formula
CuBr
2
Cu
2+
Br
-

23. Step 2 – Name
Check for the need for a
roman numeral in the name.
Transition element? Yes
“Special Case” on stair-
step? Yes

24. Step 2 – Name
Ex: Cu
2+
Br
-
Copper (II) Bromide
Your
homework
tests on these
concepts.

25. Things to look for
lIf cations have (), the
number is their charge.
lIf anions end in -ide they are
probably off the periodic
table
lIf anion ends in -ate or -ite it
is polyatomic

26. Properties of Ionic Solids
High lattice energy high melting T
3D ionic lattice  brittleness
Ions electrical conductivity (when
molten)
solubility in polar solvents (eg
H
2
O)

27. Properties of Ionic Compounds
lCrystalline structure.
lA regular repeating
arrangement of ions in the solid.
lIons are strongly bonded.
lStructure is rigid.

28. Crystalline structure

29. Do they Conduct?
lConducting electricity is allowing
charges to move.
lIn a solid, the ions are locked in
place. Ionic solids are insulators.
lWhen melted, the ions can move
around. Melted ionic compounds
conduct.
lDissolved in water they conduct.

30. Ionic solids are brittle
+-+-
+- +-
+-+-
+- +-

31. Ionic solids are brittle
+-+-
+- +-
+-+-
+- +-
lStrong Repulsion breaks crystal
apart.