Ionic Bonding
Chapter 5
Bonding
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Ch.5 ionic bonding
Ch.6 covalent bonding
What is a bond?
What is bonding?
Learning Objective
Students will learn how to predict the type
of ion that a given element forms from its
position on the periodic table.
Youtube: What are Ions | The Chemistry Journey | The Fuse
School
5.1 Simple ions
 How much an element reacts depends
on it’s valence electron configuration
 The noble gases show almost no
chemical reactivity.
 Why?
 Because they have a full valence shell of
electrons
5.1 Simple ions
Octet rule
‘Atomsreactsothattheycanachievethesame
electronconfigurationsasthenoblegases.’
‘Atoms react so that they can achieve the
same electron configurations as the
noble gases.’
Exception = ?
Scratch paper
 Write the electron configuration of
POTASSIUM
 Write the electron configuration of
CHLORINE
 How many valence electrons do each of
these elements have?
5.1 Simple ions: metals
Example: Potassium (K)
1s22s22p63s23p64s1
Potassium wants to lose it’s one valence
electron to achieve the same valence
electron configuration as Ar 
1s22s22p63s23p6
K  K+ + e
5.1 Simple ions: metals
After giving up one electron….
potassium still has 19 protons…..
but only 18 electrons.
+19-18 = +1
Because the numbers are not the same,
there is an overall electrical charge
= ION
K  K+ + e
5.1 KWS: Cation
 CATions have a positive
charge.
 “Mr Turner feels positive
about cats.”
 Metals lose electrons to
form cations.
 “Metals go Meow”
5.1 Simple ions:
nonmetals
Chlorine is reactive because it has seven
valence electrons.
1s22s22p63s23p5
If chlorine gains one electron it has the
same electron configuration has a noble
gas
Cl atom + e-  Cl- ion
1s22s22p63s23p5  1s22s22p63s23p6
5.1 Simple ions:
nonmetals
 How many total electrons does a chlorine
ion have?
 ANS = 18
 How many protons does Chlorine ion
have?
 ANS = 17
 +17-18 = -1
 Therefore the chlorine ion has a -1
charge.
5.1 KWS: Anion
Memory clue
 “An aNion has a Negative charge.”
 “Onions make us cry. We feel negatively
about onions” (anions)
5.1 Think about it…..
1. What is the name of the type of ion with
a negative charge: cation or anion?
2. Give an example of an element that
loses electrons to form an ion with a
positive charge.
Practice
Write the electron configuration for:
 Magnesium
 Oxygen
5.1 Simple ions
 What is the charge on the ion formed by
Mg?
[Mg] = 1s22s22p63s2
Mg atom  Mg 2+ ion + 2e
 Cation or anion?
 = cation
 How many electrons does Mg 2+ the ion
have?
 How many protons does the Mg 2+ ion
have?
5.1 Simple Ions
What kind of ion is formed by oxygen?
[O] = 1s22s22p4
O + 2e-  O2-
Anion!!
By gaining two electrons, oxygen is said to
have “completed it’s octet”
5.1 Worksheet
‘Lewis Dot Structures of Atoms and Ions’
5.1 Simple Ions
Misconception:
‘An atom and its ion have the same
chemical properties.’ WRONG!!!!
e.g. potassium atom vs potassium ion
An atom and its ion have different chemical
properties.
5.1 Simple Ions
Misconception:
When an atom loses/gains electrons to
form an ion, it achieves an electron
configuration identical to a noble gas.
That does not mean it becomes a noble
gas!
Ar vs Cl-
5.2 Ionic Compounds
Learning Target:
What happens when cations and anions
combine together?
‘What are Ionic Bonds? | The Chemistry Journey | The Fuse
School”
5.2 Ionic Bonds
When sodium and chlorine react…..
sodium gives it’s valence electron to chlorine.
Both elements ‘complete their octet’.
Sodium + Chlorine  Sodium Chloride (NaCl)
Element + Element  Compound
Teacher Notes:
VId: Reaction of Sodium and Chlorine
Lewis structure
5.2 Ionic Bonds
Metal + Nonmetal  Salt
In chemistry, a salt is not just sodium
chloride,
Salt = the scientific name given to many
different ionic compounds
Sodium + Fluorine  NaF (a salt)
Ionic compounds
5.2 Ionic Bonds
 What is the force that holds a salt
together?
Electrostatic attraction:
Opposites attract!
 The force of attraction between a
positive charge and a negative
charge.
5.2 Crystal lattice
5.2 Ionic Compounds
Learning Target:
What are the properties of ionic
compounds?
Standard
c. Analyze and interpret provided data
about bulk properties of various
substances to support claims about the
relative strength of the interactions among
particles in the substance.
Youtube:
Ionic Bonding (Mexus)
https://www.youtube.com/watch?v=UeNJ7v
KxcAo
5.2 Ionic Bonding
crystal lattice:
Salt crystals are made of repeating units of
anions and cations
5.2 Ionic Bonding
Ionic bonds are very strong
5.2 Ionic Bonding
 Attractive forces involve more than a
single cation and anion.
 Six Na+ ions surround each Cl ion and
 Six Cl- ions surround each Na+ ion.
Youtube:
Sodium Chloride Crystal lattice
5.2 X-ray crystallography
Born-Haber Cycle p.169
Notes: Bond
making/breaking
 Breaking chemical bonds requires
(releases/requires) energy
 Forming chemical bonds releases
(releases/requires) energy
Standard
d. Develop a representation to show that
energy is required to separate the atoms in
a molecule and that energy is released
when atoms at a distance come together to
form molecules that are more stable.
5.2 Conductivity p.172
 An ionic compound
conducts electricity
when dissolved in
water
 ‘Electrolyte’
Demo: conductivity meter
Youtube: Gatorade Hydration
Institute
:
5.2 Ionic Bonding
Notes:
“To conduct an electric current, a
substance must satisfy two conditions:
 it must contain charged particles
 those particles must be free to move”
Teacher Notes:
http://phet.colorado.edu/en/simulation/soluble-salts/ conductivity meter
5.3 Names & Formulas of
ionic compounds
Objectives
 When given the formula of a compound
we can write the name
 E.g.
NaCl =
Sodium Chloride
 When given the name of a compound we
can write the formula
 E.g.
Sodium Chloride =
NaCl
5.3 Names & Formulas of
ionic compounds
Formula  Name
The name of an ionic compound is made up of
just two words:
• First, name of the cation
• Cations have the same names as the elements.
• For example, K+ = potassium ion.
• Second, the name of the anion
• For anions, the name ends in -ide.
• For example, chlorine becomes chloride
For example, KCl is potassium chloride
5.3 Names & Formulas of
ionic compounds
Formula  Name
• For anions, the name ending changes to in ide.
•
•
•
•
•
F- = fluoride
Cl = chloride
Br- = bromide
I- = iodide
O2- = oxide
5.3 Names & Formulas of
ionic compounds
Formula  Name
• The name of a binary ionic compound is made
up of just two words: the name of the cation
followed by the name of the anion.
NaCl sodium chloride
K2O potassium oxide
Al2S3 aluminum sulfide
Practice:
• Concept Review p. 7 #16-31
• (skip # 24,28, 30,31)
5.3 Names & Formulas of
ionic compounds
Exception
• Many transition elements form more than one possible
ion
• For example, the names of the two copper ions are:
Cu+
Teacher notes: Common Ions handout
Cu2+
5.3 Transition metal ions
p.163
Example:
Cu+ = copper (I)
Cu2+ = copper (II)
5.3 Transition metal ions
p.163
If there is more than one possible ion…..
roman numerals are used to indicate the charge.
5.3 Names & Formulas of
ionic compounds
Objectives
 When given the formula of a compound
we can write the name
 E.g.
NaCl =
Sodium Chloride
 When given the name of a compound we
can write the formula
 E.g.
Sodium Chloride =
NaCl
Worksheet: Chemical Formulas and Names of Ionic
Compounds
Crystal lattice
The formula of an
ionic compound just
tells us the ratio of
ions in that
compound
e.g.
NaCl = Na1Cl1
Na+:Cl1:1
5.2 Ionic Bonding
Ionic Compounds Do Not Consist of
Molecules
There are no individual, separate
molecules in an ionic compound.
5.3 Names & Formulas of
ionic compounds
Name  Formula
 ionic compounds have no overall
charge
The rule:
 total positive charge (cations) +
total negative charge (anions) =
0
5.3 Names & Formulas of
ionic compounds p.177
Try: magnesium chloride
Procedure:
1. Write the symbol and charges for the
cation and the anion (remember sec 5.1)
2. Determine the ratio that the ions must
combine in so that their charges cancel
(Tip: look for the lowest common multiple)
3. Use subscripts to denote the ratio of
cations to anions e.g. AxBy
5.3 Names & Formulas of
ionic compounds
Chapter 5
Name  Formula
Guided Practice:
1. Sodium oxide
2. Calcium oxide
3. Aluminum oxide
Independent Practice:
• Concept Review p. 6 # 9-15
• Concept Review p. 7 # 24,28, 30,31
Finished?
• Try: p.180 #6 b,c,d #7 a,b,c
Aluminum Oxide
5.3 Names & Formulas of
ionic compounds
Example: aluminum oxide
 What is the charge on the ion formed by
aluminum?
 What is the charge on the ion formed by
oxygen?
5.3 Names & Formulas of
ionic compounds
 The Al3+ ion has three positive charges, and
the O2− ion has two negative charges.
 The cations and anions must be combined in
such a way that there are the same number of
negative charges and positive charges.
 What ratio will the aluminum ion and the
oxygen ion combine in?
5.3 Names & Formulas of
ionic compounds
 Two Al3+ cations are needed for every three
O2 anions.
 That way, there are six positive charges and six
negative charges.
 Subscripts are used to denote ion ratios.
 Therefore, the formula for aluminum oxide is Al2O3.
5.3 Names & Formulas of
ionic compounds
POLYATOMIC ION
A polyatomic ion is a charged group of
several bonded atoms with an overall
charge.
Examples:
 See Table 2 p. 178
 See Ions Sheet
 Names of polyatomic anions often have
the ending –ate or -ite
5.3 Polyatomic Ions
Learning Targets:
1. Be able to identify a polyatomic ion

e.g. cyanide = CN-
2. Be able to read a chemical formula
containing a polyatomic ion

e.g. Fe2(CrO4)3
3. Formula  Name

e.g. Fe2(CrO4)3 = iron (III) chromate
4. Name  Formula
 e.g. potassium chromate = K2CrO4
5.3 Polyatomic Ions
 Consider the polyatomic
ion hydroxide, OH Hydroxide is made of
one oxygen atom and
one hydrogen atom,
chemically attached
together
 It has a total of 9 protons
and 10 electrons.
 So the hydroxide ion has
a 1- charge overall.
5.3 Polyatomic Ions
Sodium Hydroxide
Chemical formula:
NaOH
Na+ : OH1:1
5.3 Names & Formulas of
ionic compounds
Ammonia molecule
See Ions Sheet handout
Youtube: What is a polyatomic ion?
Ammonium ion
5.3 Names & Formulas of
ionic compounds
 Consider the polyatomic ion ammonium, NH4+
 Ammonium is made of one nitrogen and four hydrogen
atoms.
 They have a total of 11 protons but only 10 electrons.
 So the ammonium ion has a 1+ charge overall.
 This charge is not found on any one atom. Instead,
it is spread across this group of bonded atoms.
5.3 Think about it…..
Polyatomic Ions
1. How many atoms are there in a nitrate
ion? NO32. How many atoms are there in a nitrite
ion? NO2ANS:
Nitrate = four atoms
Nitrite = three atoms
5.3 Polyatomic ions
Consider Rb3PO4
1. What is the name of the Rb3PO4?
2. How many rubidium ions are in one unit of
Rb3PO4?
3. How many phosphorous atoms are in one
unit of Rb3PO4?
4. How many oxygen atoms are in one unit of
Rb3PO4?
5. What is the total number of atoms in one unit
of Rb3PO4?
5.3 Polyatomics
Name  Formula
e.g. what is the formula of sodium sulfate?
Use the same procedure as for regular
monatomic ions
1. Write the charges on the cation and anion
2. Balance the charges (crossing technique)
3. Simplify and remove the 1s (if necessary)
5.3 Polyatomics
Name  Formula
e.g. what is the formula of
calcium carbonate?
Use the same procedure as for
regular monatomic ions
1. Write the charges on the
cation and anion
2. Balance the charges
(crossing technique)
3. Simplify and remove the 1s
(if necessary)
5.3 Names & Formulas of
ionic compounds
Sample Problem
What is the formula for iron(III) chromate?
5.3 Names & Formulas of
ionic compounds
Determine the formula and charge for the
iron(III) cation.
Fe3+
Determine the formula and charge for the
chromate polyatomic ion.
5.3 Names & Formulas of
ionic compounds
 To balance the charges, find the lowest
common multiple of the ions’ charges
 for 2 and 3, it is 6.
 For 6 positive charges, you need 2 Fe3+
ions.
 2  3 = 6+
5.3 Names & Formulas of
ionic compounds
For 6 negative charges, you need 3 CrO 2-4
ions.
The formula must show 2 Fe3+ ions and 3 CrO 24
ions.
The formula for iron(III) chromate is
Fe2(CrO4)3
5.3 Polyatomic Ions
Fe2(CrO4)3
 How many atoms in one formula unit?
ANS =
2 Fe3+
3 Cr
12 O
= 17 atoms in one formula unit