The Structure of the
Atom
On page 22 of your ISN, don’t forget to add to your TOC!
The Structure of the Atom
• The
atom is the smallest part of an element,
while still maintaining it’s properties.
“indivisible”“can not be divided”
Draw an atom
Electrons- have a
negative (-) charge.
They are in rapid,
continuous motion
around the nuclues
Protons-has a
positive (+) charge.
The # of protons
determines the
atomic number
Electron cloudsurrounds the nucleus
and contains the
electrons. “empty
space”
Nucleus- tiny dense cluster
of protons and neutrons in
the center of the atom
Neutron- are neutral
(No charge). The # of
neutrons+ the # of
protons= Atomic mass
Out put-Analogy of an Atom
• Use
Bohrs model and write an analogy
comparing the structure of an atom to
the solar system.
Digging deeper with
atoms
Page 24 of your ISN, don’t forget the TOC!
Electrons
•
Electrons circle the nucleus in an electron cloud.
•
The outermost electrons are called valence electrons.
•
Each level/shell can only handle so many electrons
until it is full and has to send electrons to another
level/shell.
 Level one- 2 electrons
 Level two- 8 electrons
 Level three- 18 electrons
 Level four- 32 electrons
Isotopes
• Atoms
that can have a wide range of number
of neutrons in the nucleus. Different types,
have different uses
Atomic Number
Mass Number
• Number
• Number
of protons in
the nucleus of each
atom of a given
element
of protons +
number of Neutrons
Time to practice- *Output side
• Please
draw an atom that has 5 protons, 6
neutrons, and 5 electrons. Include their
charges and correct locations. (using color!)
What is the atomic
number for this atom?
What is the atomic mass
for this atom?
Time to practice #2
• Please
draw the following pair of isotopes.
Identify the atomic mass and mass number
for each(Use color!)
N
N
Periodic Table
Page 26 of your ISN, be sure to include in your TOC!
Element
• Matter
made up of only one kind of atom
Takes up space and has mass*
Mendeleev
•
Arranged 63 known elements
•
Based on chemical properties and
atomic weight
•
Left gaps for elements he
predicted were yet to be
discovered
Atomic NumberNumber of
protons in the
nucleus
Element Name
6
C
Carbon
12.011
Symbol
Atomic Mass
Average weight of
element isotopes
Physical Properties of metals,
nonmetals and metalloids * output
Metals
•
Shiny/metallic luster
•
Solid at room temperature (except
Mercury)
•
Reflect light when polished
(luster)
•
Can bent or hammered
flat(malleable)
•
Strong and resistant to breaking
•
Have a characteristic sound when
struck with an objet
•
Have high melting and boiling
points
•
Have high densities
•
Attracted to a magnet
Non Metals
•
Exist as solids, liquids or gases at
room temperature
•
Do not reflect light well (no luster)
•
Are brittle
•
Cannot be hammered flat
(nonmalleable)
•
Can not be drawn into a wire (not
ductile)
•
Soft and bend or break easily (low
tensile strength)
•
Don’t have a characteristic sound
when struck
•
Are poor conductors of heat and
electricity
•
Have low densities
•
Are not attracted to a magnet
Metalloids
•
Are generally solid
•
Can be shiny or dull
•
May or may not be hammered flat
•
May or may not be drawn into
wire
•
May or may not be brittle
•
Conduct heat and electricity
better than nonmetals, but not as
well as metals
•
Tend to make good
semiconductors
•
Have melting and boiling points
that are widely varied
•
Have densities that are widely
varied
Electrons
Electron cloud
Energy Levels
Valence Electrons
Time to move…
• We
are going to be electrons today! Lets
go into the commons and practice 
Electron Dot Diagram
• Symbol
for the element surrounded by as
many dots as there are electrons in its outer
energy level.
S
Lets Practice
~Complete the electron dot diagram and answer the
questions
N
Element?
# Electrons?
# Valence Electrons?
Lets Practice
~Complete the electron dot diagram and answer the
questions
I
Element?
# Electrons?
# Valence Electrons?
Elements, compounds
and mixtures
Page 37-38
Output part 1
Student Output-part 1
Create a Venn diagram
Compounds
Why do element combine?
• Atoms
are most stable when their electron shells
are full.
 Compound- a pure substance containing two or
more elements that are chemically bonded
Ionic bond
•
Ionic Bonds form when electrons are transferred from one atom
to another, forming charged Ions which are attracted to each other.
Elements tend to lose or gain electrons, forming Ions, to get a 'full
other shell'.
•
Ion-Atom that is positively or negatively charged because it has
gained or lost electrons
Covalent Bond
•
Covalent Bonds involve the sharing of electrons so that all
atoms have 'full outer shells'.
Metalic Bond
•
Bond formed when metal atoms share their pooled electrons
Output• Use
the following words to complete the graphic
organizer provided
• Covalent
Nucleus
Electron cloud
Molecule
Gain or loss of electrons
Ionic vs Covalent foldable…
Front
Ionic
Bond
Covalent
Bonds
Square # 1
Ionic Bond
Covalent Bond
• Atoms
• Atoms
lose or gain
electrons
• Between
Metal and
Nonmetal
share an electron
• Between
nonmetal and
nonmetal
Square # 2
Ionic Bond
Covalent Bond
Sharing Electrons
-1 electron
+1 electron
Oxygen+Oxygen
Lithium + Flourine
Square #3
Ionic Bond
Li
Li
Covalent Bond
OO
F
+
F
-
O O
Square #4
Ionic Bonds
Covalent bonds
• LiF
• H2
• NaCL
• H20
• MgO
• Co2
Chemical Bonds &
Reactions
-
+
-
+
How Many Valence Electrons?
•
Hydrogen
•
Lead
•
Xenon
•
Sulfur
•
Rubidium
1 Valence
Electron
4 Valence
Electrons
8 Valence
Electrons
6 Valence
Electrons
1 Valence
Electron
The Octet Rule
• Atoms
will combine to form compounds in
order to reach eight electrons in their
outer energy level.
 Atoms with less than 4 electrons tend to lose
electrons.
 Atoms with more than 4 electrons tend to gain
electrons.
•
Be aware that there are some exceptions!
CONSIDER EIGHT A HAPPY NUMBER FOR
ATOMS!
Lewis Structure
(Electron Dot Diagram)
•a
way of drawing the outer energy level
electrons (valence) of an atom
• The
symbol for the element surrounded
by as many dots as there are electrons
in its outer energy level (valence)
.
Al :
Aluminum
.
.N :
.
• Examples
Nitrogen
Mg :
Magnesium
How many valence electrons do each of these atoms have?
Making an Electron Dot Diagram
Element “X” has 8 valence electrons
Write down the element’s symbol
and place the first two dots on any
side of the symbol.
.
X
X:
1
If this were an atom of an element
from group 1, you would just place the
one dot on any side of the element.
.
.X :
.
4
..
.X :
.
5
.
X:
2
.
.X :
3
Place the rest of the dots in either a
clockwise or counter clockwise manner around
the symbol, with no side receiving two dots
until each side gets one.
..
: X. :
6
..
:.X.:
7
What Would the Electron Dot Diagram
Look Like?
1 Valence Electron
6 Valence Electrons
H
O
How many valence
electrons does
each atom have?
Ne
8 Valence Electrons
Sr
2 Valence Electrons
Oxidation Number
• The
charge that an atom would have if it
lost or gained electrons; ionic charge
• Can
be helpful in determining which atoms
will interact or bond with each other
• Example:
According to electron dot diagram for Magnesium, it
has two valence electrons. Because Magnesium is
“unhappy” with two, it will typically lose them. If this
happens it will turn into a Magnesium ion. At this
point it will have an oxidation number of +2.
Mg :
Magnesium
2+
Mg
What Could the Oxidation Number Be?
H
+1 or -1 because it can
gain or lose one electron
Ne
0 because it will not
gain or lose electrons
O
-2 because it will
gain two electrons
Sr
+2 because it will
lose two electrons
3 Types of Chemical Bonds
•Ionic
•Covalent
•Metallic
What can you describe about each of these
bonds just by looking at the name?
IONIC BONDS
•
The force of attraction between oppositely charged ions.
•
Occurs after a transfer or loss/gain of electrons
•
Usually form between atoms of metals and atoms of nonmetals
•
Resulting compounds have a name that usually ends in –ide
Cl
Na 1+
1-
-
-
-
-
-
-
-
-
++ +
+ + +
+
+
-
-
-
++
+ +
+
-
-
-
-
-
-
-
Example - Sodium Chloride (NaCl)
-
Which
different
groups or
families
of elements will
+
+ most-likely
interact
to
+
create these
types
of- bonds?
COVALENT BOND
•
A force that bonds two atoms together by a sharing of
electrons
•
Each pair of shared electrons creates a bond
•
Usually occurs between atoms of non-metals
H O H
+
-
-
++ +
+ + +
+ +
-
-
-
+
-
-
Example – Water (H2O)
Results of Bonding
Molecule
A neutral group of two or
more non-metal atoms held
together by covalent bonds
Compound
A pure substance composed
of two or more different
elements (atoms) that are
chemically combined
Type:
Examples:
Diatomic - molecules consisting
of two atoms of the same
element bonded together
CO, NO2, NaCl
Examples:
H2, F2, O 2, N 2
What would you call something that has
characteristics of both?
Molecule, Compound, or Both?
Chemical Equation
•
Shorthand form for writing what reactants are used
and what products are formed in a chemical reaction
•
Sometimes shows whether energy is produced or
absorbed
•
Examples:
2H2 + O2  2H2O
CH4 + 2O2  CO2 + 2H2O
C6H12O6 + 6O2  6CO2 + 6H2O + energy
Components of a Chemical Equation
Chemical
Formula
2H2 + O2 
Coefficient
Coefficient
Subscripts
(Reactants)
2H2O
(Yield)
Subscript
(Products)
Sometimes you will see a “yields” sign that looks like this.
What do you think it means?


Chemical
Formulas
Law of Conservation of Mass
•
Proposed by Antoine Lavoisier
•
In a chemical reaction, atoms are neither created nor
destroyed
•
All atoms present in the reactants are also present in the
products
•
Chemical equations must account for/show the
conservation of mass  balancing equations
In its present form, does this chemical equation show a
conservation of mass?
2 H2 + O2  2 H2O
Reactants
H  24
O  22
How would you balance this equation to
show the conservation of mass?
Products
H  24
O  12
Hints For Balancing Equations
•
Count the atoms
 List the number of atoms of each element to see which
elements must be balanced
•
Use a coefficient to add atoms to one side of the equation
 Start with the reactant or product that has the greatest
number of different elements
•
Add a coefficient to another reactant or product
 Make sure that the coefficients in your balanced equation
are the smallest whole numbers possible (they should have
no common factor other than one)