IONIC BONDING
Belton High School
Chemical Bond
►Definition
– a mutual electrical
attraction between the nuclei and
valence electrons of different atoms
 Valence electrons are electrons
available to form a chemical bond.
These electrons are in the outermost
s and p orbital
Making Ionic Compounds
► Why
do atoms bond?
 Independent atoms are at a relatively high
potential energy.
 Bonding allows atoms to become more stable
There are two types of Chemical
Bonds
► COVALENT
 Occurs when electrons are shared between two
non-metals
 We will study these after break
► IONIC
 Occurs between METALS and NON – METALS
Formation of Positive Ions
► Metals
LOSE electrons and form POSITIVE (+)
ions.
 Positively charged ions are called cations
 Metals (main group elements, s & p blocks)
 Number electrons lost = valence electrons
 Ion charge = number of electrons lost
 Transition metals (d-block) are multivalent
 Use the chart to determine the charge
Formation of Negative Ions

Nonmetals GAIN electrons and form
NEGATIVE (-) ions.
 Negatively charged ions are called
anions
 Number of electrons gained = 8 –
valence electrons
 Ion charge = number of electrons
gained
To keep track of valence electrons,
we use an electron – dot structures
►Electron
dot diagrams represent VALENCE
electrons.
1) Write the symbol of the element.
2) Draw dots to represent valence electrons
Calculating the number of Valence Electrons
► Simple,
look at periodic table!
► On your periodic table, write the # of
valence electrons for each main group
Practice Problems
► How
many valence electrons are in the
following elements?
 Mg
►
2 val. electrons
F
►
7 val. electrons
 Na
►
1 val. electron
 Al
►3
val. electrons
Noble Gases
► Noble
gas are extremely stable due to a
completely filled s and p orbital
 Noble gases have 8 val. Electrons (except
He)
 All the other elements want to be like a
Noble Gas
► Octet Rule: Atoms lose, gain, or share to
reach an octet (8) of valence electrons.
Practice Problems
► Draw
the electron dot structures for the
following atoms:




Carbon
Neon
Barium
Silicon
Determining the Charge of Ions
► Remember
– Ions are positively or
negatively charged atoms
 Ions have either gained or lost electrons
► Start
with drawing electron dot structure,
then determine how many electrons need to
be gained or lost to achieve an octet
 Example) Fluorine
Determining the Charge of Ions
► Refer
to Periodic Table!!
Practice Problems
► Determine
 Nitrogen
►
-3
 Lithium
►
+1
 Radium
►
+2
 Chlorine
►
-1
the Charge of the following Ions
Making Ionic Compounds
► An
ionic compound is between a cation and
an anion. The positive and negative charges
must balance one another.
► The total overall charge must always equal
zero (0)
► Why do atoms bond?
 Independent atoms are at a relatively high
potential energy.
 Bonding allows atoms to become more stable
Electron Dot Structure for Ionic Compounds
►
We will use arrows to show the movement
of electrons for ionic compounds.
 The electrons always go from Cations (metal)
to Anions (non-metal)
 Therefore, your arrow always points to the
nonmetal
►
►
Example) Na and Cl
1). Ionic bond – electron from Na is transferred to Cl,
this causes a charge imbalance in each atom. The Na
becomes (Na+) and the Cl becomes (Cl-), charged
particles or ions.
Writing Formulas for Ionic Compounds
Step One – Write the ions for each atom
involved in the bond.
► Step Two – Balance the charges to make
the sum equal zero
► Example) Potassium and Oxygen
►
 1) K+1 and O-2
 2) K2O
Subscript tells you
the number of
atoms
No subscript is an
understood ONE
K+
K+
O2-
Writing Formulas
Hydrogen and Fluorine
Lithium and Oxygen
Li+
O2-
Li+
Li2O
Non Metal/Anion
Metal/Cation
HF
H+
Al3+
O2-
O2-
Aluminum and Oxygen
Al3+
Al2O3
F-
O2-
Putting Ions Together – Criss Cross
Method
Na+ + Cl- = NaCl
Ca+2 + Cl- = CaCl2
Ca+2 + O-2= CaO
Ca+2 + N-3 = Ca3N2
You try these!
Li+ + Br- = LiBr
Al+3 + I- =
AlI3
Sr+2 + P-3 = Sr3P2
Mg+2 + F- =
MgF2
Electron Dot Structure of Electron Pushing Model
Naming Ionic Compounds
►
There are three types of ionic compounds
and each one has a different naming system
 Binary Compounds – 2 ions bonded together
 Multivalent Compounds – transition metal
bonded to a non-metal
 Polyatomic Compounds – more than 2 ions
bonded together
Refer to your table of common polyatomic Ions for
naming
►
Binary Ionic Compounds
► Remember
in writing the formula, put cation
first and anion second
► Rules for naming:
 1) Name the first element
 2) Change the ending of the second element to
–ide
 For example)
►CaCl2
= calcium chloride
►MgS = magnesium sulfide
Practice Problems
► Name
the following compounds
 1) LiI
►Lithium
Iodide
 2) BaF2
►Barium
Fluoride
 3) KCl
►Potassium
Chloride
 4) CaBr2
►Calcium
Bromide
Practice Problems
► Give
the following formulas for the binary
compounds
 1) aluminum sulfide
►Al2S3
 2) potassium oxide
►K2O
 3) Aluminum fluoride
►AlF3
 4) barium oxide
►BaO
Naming Multivalent Compounds
Transition Metals (d-block) can have multiple
valence electron numbers
► Therefore you must specify the charge when
writing the name.
► Rules to naming:
►




1) Name the first element
2) Show the charge of the ion with Roman numerals
3) Change the ending of the second element to –ide
Example) Cu2S = copper (I) sulfide
Practice Problems
► Write
the name of the following multivalent
compounds
 1) Lead (II) bromide
►PbBr2
 2) Manganese (II) oxide
►MnO
 3) Iron (III) sulfide
►Fe2S3
 4) Nickel (IV) bromide
►NiBr4
Practice Problems
►
Write the formula for the following
compounds
 1) iron (II) sulfide
►FeS
 2) cobalt (III) sulfide
►Co2S3
 3) manganese (II) phosphide
►Mn3P2
 4) chromium (III) flouride
►CrF3
Naming Ionic Compounds with
Polyatomic Ions
Polyatomic Ions contain more than one
element
► There is a list of common polyatomic ions
with their names and formulas
► *** Always treat polyatomic ions as if they
are one element. They act as a group.
► Naming Rules:
►
 Name the first element
 Name the polyatomic ion (DON’T change ending
to –ide)
Practice Problems
►
Name the following compounds
 1) LiNO3
►Lithium
nitrate
 2) Ba(OH)2
►Barium
hydroxide
 3) AlPO4
►Aluminum
phosphate
 4) Be(ClO2) 2
►Beryllium
chlorite
Practice Problems
►
Give the following formulas for the
compound
 1) silver phosphate
►Ag3PO4
 2) calcium hydroxide
►Ca(OH)2
 3) aluminum nitrate
►Al(NO3)3
 4) lead (II) carbonate
►PbCO3
Oxidation Numbers
► Definition
– A number that indicates the
general distribution of electrons among the
bonded atoms
 Oxidation number of a neutral element is ZERO
 In a compound, the sum of all atoms oxidation
numbers equals ZERO
 For Ionic compounds, the oxidation number
equals the ion charge
Oxidation Number Practice
►
Determine the oxidation number for….
ZERO
 1) Mg = ______
 2) In MgO, the oxidation number of the Mg ion
+2
-2
is _____
and Oxygen ion is _______.
 3) In Ni (III) N, the oxidation number of the Ni
+3
-3
ion is _______
and the nitrogen ion is ______.
 *** Notice the sum of atoms is always ZERO for
neutral compounds.
Flow Chart for Naming
Does the compound have
more than 2 elements?
You have a binary
compound. Is your
metal multivalent?
NO
Naming:
1) Name cation
2) Name anion
changing
ending to -ide
YES
Naming:
1) Name cation
2) In roman
numerals put
charge of metal
3) Name anion
changing
ending to -ide
You have a polyatomic
Compound. Is your
metal multivalent?
NO
Naming:
1) Name metal
2) Name polyatomic
ion
Or
1) Name polyatomic
2) Name anion
changing ending
to -ide
YES
Naming:
1) Name metal
2) In roman
numerials put
charge of
metal
3) Name
polyatomic
ion
NaCl
LiBr
KF
ZnCl2
Fe2O3
Li
Na
K
Al
Fe
Cu Zn
CuI2
Al2S3
O F
S Cl
Br
I
1. What do you notice about the location of
the first element in the compounds?
Located in the metallic portion of the periodic table.
2. Based on your knowledge about the
periodic table, would you classify the first
element as a metal or non-metal?
4. Based on your knowledge about the periodic
table, would you classify the second element as a
metal or non-metal?
(non-metal portion)
5. What do you notice about the order of element
when writing a compound? 1st metal, 2nd non-metal
metal
6. All of the compounds listed have ionic bonds.
3. What do you notice about the location of the
Given your answer to question 5, develop a
second element in the substance?
definition for ionic bonding.
On the right side of the p.t. (non-metal portion)
Ionic bonds-the attraction between a metal and
a nonmetal
Atom
Boron
Potassium
# of valence
electrons
3
1
Krypton
0
Oxygen
6
Electron Dot
Structure
B
K
Kr
O
Metal or
Non-metal
Charge of
Ion
metal
B+3
metal
K+1
Non-metal
Non-metal
Kr
O-2
Part 1: Identify the following oxidation numbers:
1.
2.
3.
4.
5.
Li +1
Mg +2
0
Ne
-2
S
+4
C
6. Cs
7. Br
8. C
9. Al
10. Na
+1
-1
+4
+3
+1
11.
12.
13.
14.
15.
F -1
Ca +2
0
Kr
Si +4
-2
O
Atoms
Ions
Formula
1. Cs and S
Cs+1 S-2
Cs2S
2. Al and I
Al+3 I -1
AlI3
3. Mg and Cl
Mg+2 Cl -1
MgCl2
4. Sr and P
Sr+2 P -3
Sr3P2
5. Li and S
Li+1 S-2
Li2S
6. Ba and Br
Ba+2 Br-1
BaBr2
7. Li and O
Li+ O-2
Li2O
8. K and Cl
K+ Cl-
KCl
9. Na and S
Na+ S-2
Na2S
10. Al and S
Al+3 S-2
Al2S3
11. Ba and N
Ba+2 N-3
Ba3N2
12. Sr and O
Sr+2 O-2
SrO
13. Ca and F
Ca+2 F-
CaF2
14. Ga and Se
Ga+3 Se-2
Ga2Se3
15. Rb and S
Rb+ S -2
Rb2S
1. NaBr
Sodium bromide
2. ZnO
3. SrCl2
Strontium chloride
4. CsF
5. Mg3N2
Magnesium chloride
6. Li3P
7. BaI2
9. Al2O3
11. CdBr2
Zinc (II) oxide
Cesium fluoride
Lithium phosphide
Barium iodide
8. NaF
Sodium fluoride
Aluminum oxide
10. K2S
Potassium sulide
Cadmium bromide
12. LiCl
Lithium chloride
13. Ag3N
Silver nitride
14. Al2S3
Aluminum sulfide
15. MgF2
Magnesium fluoride
16. CdI2
Cadmium (II) iodide
18. CsBr
Cesium bromide
17. ZnO
Zinc (II) oxide
19. Ag2S
Silver (I) sulfide
20. Na2O
Sodium oxide
21. Ba3N2
Barium nitride
22. SrCl2
Strontium chloride
24. CdS
Cadmium sulfide
26. MgF2
Magnesium fluoride
23. LiF
Lithium fluoride
25. AlP
Aluminum phosphide