Intro to
Chemical
Bonds
October 13 and 14, 2014
Do Now
 Define
 Which
valence electrons
of these atoms is more likely to bond
with another atom? Explain your reasoning.
Do Now
 Valence
Electrons: the electrons in the outermost
energy level of an atom. Atoms can have a
maximum of 8 valence electrons (except helium
with 2).
 Chlorine will bond more easily because it has 7
valence electrons. It only needs 1 more electron
to have a full valence shell (8), so it is more likely to
bond than phosphorous which needs 3 electrons.
Objective
•
•
I can write the chemical
formulas for the ionic bond
that will form between two
elements.
I can draw accurate Lewis
Dot diagrams for ionic
bonds.
Agenda
 Do
Now, Objective (7 min)
 What Do You See
 Electron Dot Structures
 Intro to Ions
 Ionic Bonding Notes
 Bonding With a Classmate
 Independent Practice
 Exit Ticket
What Do
You See?
Discuss the picture above with a table partner.
What do you think the picture represents? Why
do you think all of the people are smiling? Why
do you think the people are arranged in this
order (from left to right)
Electron Dot Structure
Symbols of atoms with dots to
represent the valence electrons
IONIC BOND
bond formed between
two ions by the
transfer of electrons
Formation of Ions from Metals

Ionic compounds result when metals react with
nonmetals

Metals lose electrons to match the number of
valence electrons of their nearest noble gas

Positive ions form when the number of electrons
are less than the number of protons
Group 1 metals 
ion 1+
Group 2 metals 
ion 2+
Group 13 metals 
 Metals form Cations
ion 3+
Formation of Sodium Ion
Sodium atom
Na 
2-8-1
11 p+
11 e0
– 1e
Sodium ion

Na +
2-8 ( = Ne)
11 p+
10 e1+
Formation of Magnesium Ion
Magnesium atom

Mg 
2-8-2
12 p+
12 e0
– 2e
Magnesium ion

Mg2+
2-8 (=Ne)
12 p+
10 e2+
Some Typical Ions with Positive
Charges (Cations)
Group 1
Group 2
Group 13
H+
Mg2+
Al3+
Li+
Ca2+
Na+
Sr2+
K+
Ba2+
Learning Check
A. Number of valence electrons in aluminum
1) 1e2) 2e3) 3e-
B.
C.
Change in electrons for octet
1) lose 3e2) gain 3eIonic charge of aluminum
1) 32) 5-
3) gain 5e-
3) 3+
Solution
A. Number of valence electrons in
aluminum
3) 3 eB.
Change in electrons for octet
1) lose 3e-
C.
Ionic charge of aluminum
3) 3+
Learning Check
Give the ionic charge for each of the
following:
A. 12 p+ and 10 e1) 0
2) 2+
3) 2B. 50p+ and 46 e1) 2+
2) 4+
3) 4-
C. 15 p+ and 18e1) 3+
2) 3-
3) 5-
Formation of Ions from Nonmetals
In ionic compounds, nonmetals in 15, 16,
and 17 gain electrons from metals
Nonmetal add electrons to achieve the
octet arrangement
Nonmetal ionic charge:
3-, 2-, or 1-
 Nonmetals form anions
Fluoride Ion
unpaired electron

:F

2-7
9 p+
9 e0
+ e
octet
: F:

2-8 (= Ne)
9 p+
10 e1ionic charge

THOUGHT ACTIVITY
•
•
Quietly answer 1-4 on your own.
Turn and talk to your partner
about a solution for #5.
1. How many valence electrons does magnesium have?
__________
2. How many valence electrons does a magnesium atom have to gain or lose to become a magnesium ion?
________________________________________
3. How many valence electrons does chloride have?
__________
4. How many valence electrons does a chlorine atom have to gain or lose to become a chlorine ion?
________________________________________
5. How might these two atoms make a compromise so that they are both stable (happy)?
____________________________________________________________________________________
IONIC BOND: electrons are
transferred from one atom to another
so they both will be stable
•
Between a CATION and an ANION
•
•
ANSWER ON YOUR OWN (30 sec): Why do you
think a cation and an anion are bonded
together?
Between a METAL and a NONMETAL
•
ANSWER ON YOUR OWN (30 sec): Why can
metals and nonmetals easily form ionic bonds?
BrainPop Video
 http://www.brainpop.com/science/matt
erandchemistry/chemicalbonds/
EXPLORE
FURTHER
•
•
Draw the electron dot diagrams
on your own.
Turn and talk to your partner about
the 2nd question.
Draw the electron dot diagram for Mg and Cl.
If these two were to transfer electrons, think about how many atoms of each you need for every atom
to satisfy a full octet.
CRISS-CROSS
RULE
1.
2.
3.
Write the ion
(charges) for
the atoms
involved.
Criss-cross the
charges and
bring them
down as
subscripts.
Simplify if there
is a common
factor.
EX 1: Mg + Cl
Copy my
example!
Copy my
example!
cRISS-CROSS RULE
1.
2.
3.
Write the ion
(charges) for
the atoms
involved.
Criss-cross the
charges and
bring them
down as
subscripts.
Simplify if there
is a common
factor.
EX 2: What is the ionic
bond that is formed
between Li and F?
cRISS-CROSS RULE
1.
2.
3.
Write the ion
(charges) for
the atoms
involved.
Criss-cross the
charges and
bring them
down as
subscripts.
Simplify if there
is a common
factor.
COMPLETE
PRACTICE
1-3 on your
own!
LEWIS DOT DIAGRAMS for
IONIC BONDS EX 1: Mg + Cl
1.
2.
3.
4.
Determine stable ion
for each element.
Draw LD for cation.
Draw LD for anion.
Write number of ions
in bond in front of LD
LEWIS DOT DIAGRAMS
for IONIC BONDS
EX 2: Draw the Lewis
1.
2.
3.
4.
Determine stable ion
for each element.
Draw LD for cation.
Draw LD for anion.
Write number of ions
in bond in front of LD
Dot diagram for the
ionic compound
Ca3N2.
IONIC BONDING WITH A
CLASSMATE
 DIRECTIONS:
1.
2.
Everyone is assigned an element.
You must find 5 classmates who you can
make an ionic bond with.
When you find them, write the formula of your
bond and draw the Lewis dot diagram for
your bond
 EXPECTATIONS:
•
•
Work efficiently!
Talking science only! (low voices)
CLASSWORK
COMPLETE
•
•
•
#1-11
Independently
Quietly
Raise a hand for ?’s
EXIT TICKET
•
•
•
•
Put all materials away
Try your best!
NO TALKING!
Finished? Raise your hand and
work on HW.
Chemical Bonds Day 2
 Students



will gain practice
Balancing ionic compounds
Naming ionic compounds
Drawing Lewis structures for covalent
compounds
Do Now
What conditions favor the formation
of ionic compounds?
1.
a.
b.
c.
d.
1.
Both atoms must be nonmetals
A metal and a nonmetal
Both atoms must be metals
Must have a metal atom and a noble gas
atom
What is the definition of a covalent
compound?
Do Now
What conditions favor the formation
of ionic compounds?
1.
a.
b.
c.
d.
Both atoms must be nonmetals
A metal and a nonmetal
Both atoms must be metals
Must have a metal atom and a noble gas
atom
Do Now
What compound would the
following ions form?
1.
a.
b.
c.
2.
H and Br
Mg and Cl
Ca and F
What group would element X be
found in if it forms this
compound: Al2X3
Do Now
What compound would the
following ions form? Criss-Cross!
1.
a.
b.
c.
2.
H and Br  HBr
Mg and Cl  MgCl2
Ca and F  CaF2
What group would element X be
found in if it forms this compound:
Al2X3
 X is in group 2 (reverse criss-cross)
Objective
I
can name ionic compounds including
polyatomic ions and transition metals
using independent practice
Agenda
1.
2.
3.
4.
Do Now, Objective
Catalyst Activity
Naming Ionic Compounds
Going Backwards
CATALYST ACTIVITY
You will have 8 minutes to circulate the
room and find the chemical formulas and
names of common household products.
Debrief Activity:
1.
Which type of ion is listed first in each chemical
formula? Which is second?
2.
Which type of element is named first in the
compound name? Named second?
3.
Are there any changes to the name of either
element when bonded?
4.
How do you think ionic compounds are
named?
STEPS FOR NAMING IONIC
COMPOUNDS
FOR YOUR INFORMATION
PRACTICE
GOING BACKWARDS:
From Name  Formula
PRACTICE
Independent Practice
 Complete
the independent practice at
your table, and turn it in for an accuracy
grade at the end of class.
Day 3
 Polyatomic
ions
 Transition metals
 Weekly quiz