Chapter 7
Ionic and Covalent Bonds
Review
Chemical Bonds form between 2 or more atoms to
form molecules
Two types of chemical bonds:
Ionic Bonds & Covalent Bonds
Ionic Bonds & Covalent Bonds
Ionic Bonds- Electrons are transferred between a
metal and a non-metal
Covalent Bonds- Electrons are shared between
two non-metals
Remember: The “stairs” on your periodic table
separate the metals and non-metals
In this Chapter…
You will understand HOW and WHY Ionic and
Covalent Bonds form
To start- remember that an element becomes stable
with 8 Valence Electrons
Hydrogen and Helium are exceptions, they only
need 2 to be full
Atoms will give, take, or share electrons to get to 8
Valence Electrons
Electronegativity
Ability of an atom to gain an electron.
Electronegativity
When two atoms have a big difference in
electronegativity the electron gets transferred
When there is a small difference the atoms share the
electron
This is WHY the atoms form the type of bonds that
they do
Ionic Bonds
Form between a metal and a non-metal
There’s usually a big difference in electronegativity,
which causes the metal to give its electrons to the
non-metal
Example: K and O (3.5 - .8 = 2.7 difference)
They transfer enough electrons so that both the
metal and non-metal have 8 Valence Electrons
Ions
When atoms give or take electrons they become
charged Ions
Metals lose electrons to become cations (+)
Non-metals gain electrons to become anions(-)
Opposite charges attract, ions come together to
form neutral molecules
Ion Formation
To figure out what ion an element will form:
If it is a metal: Find out the number of valence
electrons it needs to LOSE to get to zero.
Many Transition Metals can form more than 1 Ion
If it is a non-metal: Find out the number of valence
electrons it needs to GAIN to get to 8
Hydrogen can both lose and gain 1 electron
Practice
For each element, find out the ion that it forms
Chlorine:
Beryllium:
Argon:
Simple Ion Nomenclature (naming)
Simple cations are named by saying the element
and adding the word “ion.”
Na+ is called “sodium ion”
Mg2+ is called “magnesium ion”
Simple anions are named by dropping the
ending off the element name and adding “ide.”
F- is called “fluoride”
O2- is called “oxide”
N3- is called “nitride”
Practice
For each element, name the ion that it forms
Chlorine:
Beryllium:
Argon:
Ionic and Covalent Bonds
Day 2
Element
1 Sodium
2 Bromine
3 Magnesium
4 Chlorine
5 Oxygen
6 Boron
7 Lithium
8 Neon
Symbol
Na
Br
Mg
Cl
O
B
Li
Ne
Name
Sodium Ion
Bromide
Magnesium Ion
Chloride
Oxide
Boron Ion
Lithium ion
Neon
Formula
Na+
BrMg2+
ClO2B3+
Li+
Ne
Phosphorus
10 Aluminum
11 Calcium
12 Iodine
13 Nitrogen
14 Cesium
15 Sulfur
16 Fluorine
17 Potassium
18 Barium
P
Al
Ca
I
N
Cs
S
F
K
Ba
Phosphide
Aluminum ion
Calcium Ion
Iodide
Nitride
Cesium ion
Sulfide
Fluoride
Potassium Ion
Barium ion
P3Al3+
Ca2+
IN3Cs+
S2FK+
Ba2+
Hydrogen
20 Helium
H
He
Hydride AND Hydrogen ion
Helium
H+ AND HHe
9
19
Ions Shortcut
Pull out your periodic tables!
Group 1 = 1+
Group 2 = 2+
Group 13 = 3+
Group 14 = 4+ or 4- ***Depends on what it bonds with
Group 15 = 3Group 16 = 2Group 17 = 1-
Simple Ionic Compounds
Ions come together to form neutral compounds
Today we will learn how to:
 Write the chemical formula of the compound
created
 Figure out the name for the compound
Chemical Formulas of Ionic Compounds
We write chemical formulas of ionic compounds
using the criss-cross method
With the criss-cross
method you use the
charge of the cation
to figure out the
subscript of the
anion and vice versa
Criss - Cross Method
When possible, reduce the subscripts to get the most
simple version of the chemical formula
Situation 1: Ions with the same charge
Mg2+ and O2- would be written as MgO, NOT Mg2O2
Situation 2: Any subscript with a 1
Mg2+ and Cl- would be written as MgCl2 NOT Mg1Cl2
Naming Ionic Compounds
When naming ionic compounds, simply write the
element name of the metal followed by the ion
name of the nonmetal.
The metal ion (cation) is always written first
The name of the metal is capitalized while the ion
of the non-metal is not
NaCl is called “Sodium chloride”
CaCl2 is called “Calcium chloride”
Practice
Mg 2+ and Br - form what compound?
Al 3+ and O2- form what compound?
Ionic Bonding Day 2.5
Today
Mini-quiz: How to find Ions
Review how to write formulas for Ionic Compounds
Discuss how to name Ionic Compounds
WHY Ionic Bonds form the compounds they do
HW: Ionic Bonding WS
Mini-Quiz: Take out a half sheet of
paper and your periodic table
What Ions do the following elements form?
S
Li
Al
Ne
Br
Naming Ionic Compounds
Use the “Criss-Cross”
Method to write ionic
compounds:
 If the charges have
the same number, you
do NOT write the
subscript
If the number is a 1,
you do NOT write the
subscript
Practice- Take out your worksheet
from yesterday
1. Na and Br:
Na+ and Br- so NaBr
2. Ca and Cl
Ca2+ and Cl- so CaCl2
3. Mg and S
Mg2+ and S2- so MgS
Try #4 Al and O
and
#5 Li and P
Naming Ionic Compounds
When naming ionic compounds, write the element
name of the metal followed by the ion name of
the nonmetal.
NaCl is called “Sodium chloride”
CaCl2 is called “Calcium chloride”
Practice
11. K and O
12. Mg and I
13. Al and Cl
Try #14 Ca and Br and #15 Na and N on your own!
Ionic Bonds Day 3
Polyatomic Ions
Polyatomic Ions
A polyatomic ion is made up of 2 or more atoms
that are covalently bonded, but have an overall
charge
Even though they are multiple atoms, we treat it
like 1 ion
A list of polyatomic ions with their charges is given
on your reference sheet– you need to keep this
safe!
Polyatomic Ions in Formulas
Still use the same criss-cross method
Since the subscript applies to the ENTIRE
polyatomic ion, the ion goes in ( ) with the
subscript on the outside
Example: Mg and OH
Mg2+ and OH- form Mg(OH)2
Practice writing formulas
K and SO4
Al and NO3
NH4 and Cl
Naming polyatomic ions
Look up the name of the polyatomic ion using the
polyatomic reference sheet
The regular ion uses the same naming as usual
 Full name for Cation (+)
 -ide ending for Anion (-)
Examples: Mg and OH
Na and MnO4
Magnesium Hydroxide
Sodium Permanganate
Practice Naming
K and SO4
Al and NO3
NH4 and Cl
Ionic Bonding Day 4
Transition Metals
Transition Metals
Even though transition metals technically have 2
valence electrons, they don’t act like it
Transition Metals can form a wide variety of
cations
We will use our reference sheet to see what ions
the various transition metals can form
Figuring out transition metal charge
If the ion that goes with the metal does NOT have a
subscript, then the metal has the same charge as the
other ion
AuCl = Au+ because Cl-
FeO = Fe2+ because O-2
If the ion that goes with the metal DOES have a
subscript, then the metal has the ion charge of the
subscript
AuCl3 = Au3+ Fe2O3 = Fe3+
Practice
What is the charge on Zn in ZnCl2?
What is the charge on Cr in CrO?
What is the charge on Co in CoBr3?
What is the charge on Ni in NiSO4?
Figuring out ion charge without the
formula
Without the formula given, you cannot know which
ion charge to use (when there is more than one
choice)
When the formula is not given, you must write the
formula for all possible ion choices
Example: What is the formula for Cu and Cl?
CuCl and CuCl2 are both the correct answer, you
need both!
Practice
What are the possible formulas for…
Fe and N?
Ag and Br?
Au and O?
Naming Transition Metals
Two types of names- standard and common name
Standard name: Regular metal name with the ion
number in roman numerals in parenthesis
Example: Fe2+ Iron (II)
Common name: Based on Latin Names
Example: Fe2+ Ferrous
Both are found on your transition metals reference
sheet!
Practice
Name CuCl2 with both the standard and common
names
Name AuCl and AuCl3 with their standard names