PUTTING ATOMS TOGETHER
Chapter 7
TERMINOLOGY
Molecule – two or more atoms of the same or different elements
that are chemically joined together in a unit.
nitrogen
20%
• Ex. Air = roughly 80% _______________
molecules, _____
oxygen molecules, and trace amounts of H2O and
CO2
TERMINOLOGY
notation
that
indicates
the
type
and
number
Chemical Formula –
of atoms in a pure substance
above/after in chemistry
•Superscript - small numbers written ____________,
usually indicates a charge  Mg2+
below/after tells us how many
• Subscript – small number ___________,
atoms there are  O2 = 2 oxygen atoms
Diatomic Elements – Elements that exist as molecular elements
consisting of 2 atoms.
*7
DIATOMIC MOLECULES
These seven elements occur naturally as molecules containing two
atoms. “HONClBrIF”
• What element is
this?
• How many
valence
electrons does it
start off with?
• How many does
it end up with
once it forms a
bond?
MOLECULAR
COMPOUNDS
Sharing is caring!
What do we call rxn’s that release
energy/heat?
What do we call rxn’s that require it?
TERMINOLOGY
Molecular Compounds –
Compound consisting of two
or more different elements
with neutral charges that are
bonded together.
non-metal
• Involves two _______________
(includes hydrogen) elements
joining together and sharing
valence electrons to fill
their ________
energy level
their outer __________________
(shell).
A simulation of the reaction:
2H2 + O2

2H2O
Means electrons “LEAN” or
migrate towards one molecule
creating partial + and - charges
Forces that hold atoms together
Represent “potential” energy
Illustration to the right
hydrogen
shows two __________
molecules and a single
oxygen
_______ molecule.
Hydrogen wants to have a
full valence
________ shell (first shell
2
can hold a max. of __)
meanwhile the oxygen
atom also wants to have a
full valence shell (2nd shell
8 Therefore a
can hold __).
sharing of electrons
____________________
occurs.
2H + 1O

H2O
A key aspect of molecular compounds is the fact they are
dependent____
on arrangement
______________________
____________________. Only certain
combinations in __________
are found in nature.
fixed _______________________
amounts
Ex. O2 = Oxygen Gas, meanwhile O3 = Ozone
•The above example highlights the fact that a change in
configuration
______________________________________
dramatically changes the
compound and how it affects us.
______________________________________________
These molecules can be drawn as
Bohr-Rutherford
__________________________________________
diagrams or as
Lewis dot diagrams
____________________________________
with the shared pair of electrons
represented by a _____, 2 pairs by a ______, or 3 sets of shared
electrons by _____. The most that will ever be shared is 3.
IONIC COMPOUNDS
TERMINOLOGY
• Def. Ionic Compound:
Compound consisting of a positively charged (cation)
and negatively charged (anion) ion.
metal
• Involves a ___________
+ a _____________
joining
non-metal
giving away
together, with the metal _____________
its
___________
_________
valence
electrons and the __________
non-metal taking
them.
IONS
a particle that has a + or - charge
• Def. Ion –_________________________________
2 forms
Cation = Positive
1. _________
Anion = Negative
2. _________
WHY DOES THE METAL ALWAYS GIVE
AWAY ITS VALENCE ELECTRONS AND
THE NON-METAL ALWAYS TAKE THEM?
• Think about this
silently (use your
notes or textbook
as a reference)
ANSWER
• It is easier for a metal to give up 1 to 4
electrons than try to take enough to fill its
valence shell.
• For non-metals, they generally only need 1 or 2
extra’s to fill their shells, so it is easier for them
to take 2 than give up 6.
• Based on strength of nuclear charge
• When an atom gains an electron, it becomes
negatively charged (more electrons than protons ).
anion
• This is called an ________
• In the same way that non-metal atoms can gain
electrons, metal atoms can lose electrons.
• They become positively charged cations
________.
IONS
Here is a simple way to remember which is
the anion and which the cation:
This is Ann Ion.
Two N’s in
ANION
for
Negative
This is a cat-ion.
A “T” in
CATION for
Positive
She’s unhappy
and negative.
He’s a “plussy” cat!
IONIC RADIUS
• Cations are always smaller than the original atom.
• The entire valence shell is removed during ionization.
• Conversely, anions are always larger than the
original atom.
• Electrons are added to the valence shell to fill it up
(stabilize it).
# of + Charge
(Protons)
# of - Charge
(Electron)
Overall
Ionic charge
Sodium
Sodium
Chlorine
Chlorine
Atom, Na
Ion, Na+
Ion, Cl-
Atom, Cl
IONS
• Based on the way the periodic table is arranged, we
already know/can predict the change of an ion based
on the _____________
it belongs to.
family
• This is all based on its ____________
Valence _________.
electron
DRAW DIAGRAM FROM TEXT
(pg. 260)
• Copy the Bohr-Rutherford
• Create a Lewis Dot Diagram
• Draw a bohr-Rutherford diagram of sodium and chlorine combining to form
sodium chloride.
• Draw a lewis-dot structure of the same reaction
Sodium Ion, Na+
Chlorine Ion, Cl-
HW  Q 1-8 on page 261
PERIODIC TABLE WORKSHEET
REVIEW
Metals are located on the left side of the
1. _______
non-metals located on the right
periodic table, with __________
staircase that
side. They are separated by a “________”
touches the __________.
metalloids
periods and tell us
2. Horizontal rows are known as ________
shells an element
the number of Energy
______ levels
_____ or ______
has.
Families or groups are vertical ________
columns on the
3. ________
periodic table and tell us how many valence
electrons an element has.
_________
4. ATOMS have the same number of Protons as
atomic _______,
number so their charge is neutral, this
they do ______
charge
information is detailed in the ______.
charge because
5. IONS have a positive or negative _______
they have given up their valence
_______ electrons
_________ or taken
valence electrons from an atom of another element in
order to fill/empty their outer energy shell.
cations (think the t looks
6. Positive ions are known as _______
anions (has two
like a +) while negative ions are called _______
n’s for negative).
MAGNESIUM ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Draw a Bohr-Rutherford Diagram
LITHIUM ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Draw a Lewis-Dot Diagram
ARGON ATOM
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
• Symbol =
• Period # =
• # of energy levels =
• Group # =
• # of Valence Electrons =
• Member of the _____________ Family
• Number of Neutrons =
• Draw a Lewis Dot diagram
FLUORINE ATOM
ION REVIEW
a) An ION of fluorine is going to mimic (look like) an atom
Neon
of ______.
b) An ION of beryllium is going to mimic an atom of
Helium
__________________.
phosphorus has to gain 3 electrons to
c) An ION of ____________
-3
mimic argon. Its ionic charge will be ____.
d) An ION of Aluminum
_________ has to give up 3
electrons in order to mimic an atom of neon. Its
+3
charge will be ___.
gain ___
2 electrons to
e) An Ion of Oxygen has to ____
neon Its ionic charge will be ___.
-2
mimic _____.
CALCIUM ATOM
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass (most common isotope) =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
OXYGEN ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass (most common isotope) =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
CHLORINE ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass (most common isotope) =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
ALUMINUM ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass (most common isotope) =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
POTASSIUM ION
• Symbol =
• Atomic # =
• # of Protons =
• # of Electrons =
• Ionic Charge =
• Atomic Mass (most common isotope) =
• Number of Neutrons =
• Draw a Bohr-Rutherford Diagram
QUESTIONS FROM READING
1. How do atoms become more stable?
2. When metals mix with another metal is it called an
________.
3. When metals mix with non-metals it is called an
__________ compound.
a) What happens with the electrons in these
compounds?
4. When two non-metals mix it is called a ____________
compound.
a) What happens with the electrons in these
compounds?
Pop Quiz
1.
2.
3.
4.
5.
What is an ion?
What do we call positive & negative ions?
Describe ionic compounds /2
Describe molecular compounds /2
What type of compounds are the following… how many atoms in
each?
•
•
•
•
Water – H2O
Methane – CH4
Table salt – sodium chloride – NaCl
Potassium oxide – K2O
6. What element does a Lithium ion mimic
7. Draw a B-R diagram of a fluorine atom
8. Draw a B-R diagram of a magnesium ion
BUILDING MOLECULES
THINK ABOUT IT
If you were told that an ionic compound formed between a
single oxygen ion and a single metal ion, which family would
you expect the metal to belong to and why?
If you were told that an ionic compound formed between
two magnesium ions and a single non-metal ion, what
element would you expect to see bonded with the
magnesium?
If nitrogen gas was going to bond with an alkali metal, how
many metal ions would you expect to see bonded?
THINK ABOUT IT
If you were told that an ionic compound formed btw a
single oxygen ion and a single metal ion, which family would
you expect the metal to belong to and why?
Alkaline earth metal, because their charges balance out…
Oxygen is two away from being stable, so it wants 2
electrons… making it a negative 2 (-2)
Family two elements have 2 valence electrons, so they want
to give away 2 electrons, making them positive 2 (+2)
THINK ABOUT IT
If you were told that an ionic compound formed between
two magnesium ions and a single non-metal ion, what
element would you expect to see bonded with the
magnesium?
Carbon!
…or some other family 14 non-metal
This is because each magnesium releases two electrons (-2
charge) for a total metal charge of negative 4 (-4)
You need a non-metal looking for 4 electrons to balance it
THINK ABOUT IT
If nitrogen gas was going to bond with an alkali metal, how
many metal ions would you expect to see bonded?
3!
…nitrogen is 3 away from being stable (full valence shell), so
it wants to steal 3 electrons.
Since alkali metals only have 1 valence electron, nitrogen
must bond with 3 atoms of a alkali metal to fill its valence
shell
IONIC COMPOUNDS
Names & Formulas
A ionic compound is made up of
positive and negative ions (cation and
anion) joined together by ionic bonds.
A ionic bond result
from a transfer of
one or more
electrons from one
atom to another
then joint together
by electrostatic
forces of attraction.
For example, the arrangement of Na+ ions and Cl- ions in a
crystal of sodium chloride. Each Na+ ion is surrounded by six
neighboring Cl- ions, and each Cl- ion is surrounded by six
neighboring Na+ ions.
REVIEW
Compound consisting of a positively charged (cation) and
• Def. negatively charged (anion) ion.
metal
non-metal
• Involves a ___________
+ a _____________
joining
giving away its ___________
valence
together, with the metal _____________
non-metal taking them.
electrons and the __________
_________
a particle that has a + or - charge
Def. Ion –_________________________________
 2 forms
Anion = Negative
1.) _________
Cation = Positive 2.) _________
NAMING
Ionic compounds are easily identified by the presence
metal (first term). Any time you see a metal as
of a ___________
the first term, you should automatically be thinking
NUMERICAL
IONIC! Additionally, there is never a __________________
reference in the compound name (so no
PREFIXES
_________________).
The nice thing about naming Ionic
DO NOT need to worry about
molecules is we __________
numbers (subscripts).
Example  K2O
1)Determine how many elements (each capital letter
represents a new element) are present in the compound
2
(_______)
and locate them on the periodic table. Is there
a metal..? If so it must be a Ionic Compound.
2) Identify which of the elements is the metal (it must go
Potassium
first). __________________
3) Identify the non-metal element (it goes 2nd).
Oxygen
____________________
4) Write the name of the metal, than the name of the nonmetal (but change the ending of the non-metal to
Potassium _____________
oxide
“IDE”). ___________
Try these…
Li2O
Lithium oxide
CaS
Calcium sulphide
MgF2
Magnesium fluoride
Be3P2
Berylium phosphide
NaCl
K3N
Sodium chloride
Potassium nitride
LiBr
Na2O
Lithium bromide
Sodium oxide
WRITING CHEMICAL FORMULAS FOR
IONIC COMPOUNDS
given/taken and electrical
Since the electrons are ____________
charges
_______ are present we need to reference the
Periodic Table in order to determine how many of
each element there is going to be.
THE CHARGES MUST BALANCE
____________________________!
Step 1: Locate the elements in the Periodic Table- ensure
one is a metal, and one is a non-metal. Write down their
chemical symbol.
Step 2: Determine the “charge” each element carries when
its forms an ionic bond (remember: how far from STABLE)
Step 3: Backcross the “charges“ to SUBSCRIPTS for each
+1 -2
element
Rb O
Ex.
+1 -2
Rb O
Rubidium “charges it up” _____
_____  “backcross it down”
oxide
Rb2O1
Compound
Sodium
chloride
Magnesium
nitride
Calcium
fluoride
Francium
phosphide
CHARGE
Na+1 Cl-1
Mg+2 N-3
Ca+2 F-1
Fr+1 P-3
FORMULA
NaCl
Mg3N2
CaF2
Fr3P
MOLECULAR COMPOUNDS
Names and Formulas
NAMING MOLECULAR COMPOUNDS
Molecular compounds are made of 2 or more non• Def. metals only. Non-metal atoms SHARE electrons
with each other via COVALENT bonds.
• This means there is no taking or giving of
electrons, therefore there is no _________
IONS
These compounds are…
a) Soft, do not form crystals
b) Have a low melting point
c) Do not dissolve in water
d) Do not conduct electricity
e) Solids, liquids, and gases
easily identified
• Molecular compounds are _____________________
by the use of PREFIXES. Anytime you notice a
numerical prefix in a compound, you should
automatically be thinking MOLECULAR and NONMETAL atoms.
Mono
Di
Tri
1
2
3
Tetra Penta Hexa Hepta
4
5
6
7
Octa
8
EXAMPLE 
H2O
STEP 1: Determine how many elements (each capital letter
represents a new element) are present in the compound
(_______)
and locate them on the periodic table.
2
STEP 2: How many HYDROGEN (H) atoms are there?
________
2
STEP 3: How many OXYGEN (O) atoms are there?
1
________
STEP 4: Write the corresponding prefixes first (on the smaller
lines), then the name of the element on the larger lines,
remember to always change the ending of the second
element to “IDE” just like we did yesterday with IONIC
compounds.
________
Di _______________
hydrogen
Mon
_____ ____________
oxygen
ide
TRY THESE
N2O
BrI
Dinitrogen monoxide Bromine monoiodide
ICl2
Iodine dichloride
S2Cl2
Disulphur dichloride
XeF4
Xenon tetraflouride
UF6
ClO2
Chlorine dioxide
P2O5
Uranium hexaflouride Diphosphorus pentaoxide
REMEMBER: first term never includes mon(o)
WRITING CHEMICAL FORMULAS
FOR MOLECULAR COMPOUNDS
• The ______________
in-front of the element tells
PREFIX
atoms
you how many ______________
(units) of that
element there are in the formula. These numbers
are to be written as SUBSCRIPTS after the
elements symbol.
• STEP 1 – write the symbol for each element on
the top lines
• STEP 2 – write the corresponding prefix number as
a subscript (below and after) each elements
symbol
• Ex. Dinitrogen tetraoxide 
N2 O
___
4
___
TRY THESE
Notice that the first term
sometimes lacks a prefix…
what does this mean again?
Nitrogen
dioxide
NO2
Dinitrogen
monoxide
N2O
Sulphur trioxide
SO3
Diphosphorus
pentasulphide
P2S5
WORKSHEET
• Work through all the sections
• Try to do it without using your notes to see
what sections you need to focus on when it
comes time to study
IONIC – NAMES
KBr
Al2S3
Potassium
bromide
Aluminum
sulphide
MgO
ZnS
Magnesium oxide
AlCl3
Zinc sulphide
Aluminum
chloride
Ionic – Formulas
Magnesium Potassium
Chloride
Nitride
MgCl2
K3N
Sodium
bromide
NaBr
Aluminum
sulphide
Al2S3
Aluminum
chloride
AlCl3
Molecular – Names
P2O5
Diphosphorus
pentaoxide
SO2
AsBr3
Arsenic
Sulphur dioxide tribromide
P4O6
CO
Tetraphosphorus Carbon
monoxide
hexaoxide
Molecular – Formulas
silicon
dioxide
SiO2
carbon
disulfide
CS2
diboron
tetraphosohorus diphosphorus
tetrabromide
hexaoxide
pentaoxide
B2Br4
P4O6
P2O5
Mixed – Names
CS2
MgI2
Magnesium
Carbon disulphide iodide
KF
N2O4
Potassium
flouride
Dinitrogen
tetraoxide
P4O6
Tetraphosphorus
hexaoxide
Mixed - Formulas
Silicon
dichloride
SiCl2
magnesium
chloride
MgCl2
diphosphorus
trioxide
P2O3
potassium
nitride
K3N
dinitrogen
tetraoxide
N2O4
• Build the molecule using the ball and stick
kits
• Build the metal atom using the BR kit… how
would you turn it into an ion?
• Draw a Bohr-Rutherford diagram of the
reaction
• Draw a Lewis-dot structure of the reaction
END OF CHAPTER
7