Which scientist is credited
with the discovery of
electrons by experimenting
with Cathode Ray Tubes?
1
Atomic
Structure
Notes
Atomic Structure
subatomic _________
particles .
Atoms are made up of __________
protons _________
neutrons
Subatomic particles include ________,
electrons
and _________.
________
Protons and _________
neutrons
are inside the ________
nucleus
__________
Electrons are found
__________
outside
the nucleus
3
Subatomic Particles
Protons have a _________
+
charge and
1 AMU
a mass of ________.
1 AMU = Atomic Mass Unit
neutral charge
Neutrons have a _________
1 AMU
and a mass of _________.
Electrons have a _________
charge and
small that we
a mass that is so ______
consider electrons to have “NO”
____ mass!
4
Number of Protons
Elements in the Periodic Table are
Atomic ________.
number
organized by ________
The atomic number is the same as
protons
the number of ________.
different
Every element has a _________
number of protons, and therefore a
different
________ atomic number.
5
Atomic Number = # protons
6
Number of Electrons
neutral atom, the number of
In a _________
protons always equals the number of
_________
electrons
__________.
#p = #e
7
Electron Practice
Find the number of protons and
electrons in the following atoms:
Symbol
Protons
Electrons
Mg
12
12
O
8
8
Au
79
79
Ti
22
22
8
Atomic Mass
An atom’s mass is the sum of its parts
1
Proton = ________
amu
1
Neutron = ________
amu
0
Electron = ________
amu
Since the electron has practically no mass
we don’t count it in the mass of the atom
9
Atomic Mass
You can find the mass of an atom from
Periodic _______
Table
the __________
For us, that mass is the sum of the
Neutrons .
Protons and __________
__________
Fluorine has -
9
__________
protons
19
__________
neutrons
10
Atomic Mass = # protons + # neutrons
11
Number of Neutrons
To get the number of neutrons, get the
Periodic ______
Table
atomic mass from the _________
and subtract from that the number of
protons
________.
#neutrons = Atomic Mass - #p
12
Neutron Practice
Find the number of p, n and e in the
following atoms:
Symbol
Protons
Neutrons
Electrons
Na
11
12
11
B
5
6
5
H
1
0
1
C
6
6
6
13
14
Atomic Structure wkst
Textbook Packet
15
How many neutrons does
a lead atom have?
16
Qz: Atomic Structure
17
Element Symbols
symbol on the
Every element has a _________
Periodic Table.
The symbol is either 1 or 2 letters, where
CAPITAL letter, and
the first is always a _________
small letter…
the second is always a _______
H He
C
Ca
18
Element Notation
Element symbols contain the atomic
number, mass number and element
symbol.
Mass
number
Atomic
number
J
Element
symbol
19
Element Notation
Complete the notation for the following:
39
19
K
27
13
Al
20
Atomic Structure wkst
Textbook Packet
coninued
21
Identify the atom that has
26 neutrons, 22 protons
and 22 electrons.
22
BELL RINGER
Draw the electron
dot diagrams for
Chlorine and
Sodium.
BELL RINGER
How many electrons
does a phosphorus
atom have?
Neutrons?
BELL RINGER
Draw the Bohr
diagrams for
Lithium and
Oxygen.
The Bohr Model
Basic Layout
nucleus is in the center of the atom
The ________
protons and
and contains both _________
electrons and the ___________
neutrons are found
__________,
orbiting the nucleus.
Electron Energy Levels
energy levels
• Electrons are found in _______
around the nucleus.
lower
closer to the nucleus, the ________
• The _______
the energy of the electrons.
farther from the nucleus, the
• The _______
higher the energy of the electrons.
________
Electron Configuration
arrangement of
Electron configuration is the ___________
electrons outside the nucleus of an atom.
The 1st energy level holds up
2 electrons.
to ____
2nd level holds up to ___
8
3rd level holds up to ___
18
Electron Configuration
You don’t have to memorize this, use the Periodic Table
Look under the
atomic number and
you will see where
the electrons will go
For Oxygen, there
2 electrons
are ___
in the 1st level and
6 electrons in
___
the 2nd level.
How to: Bohr Models
Rules
protons in the ________
nucleus
1. Put the number of _______
neutrons in the ________
2. Put the number of _________
nucleus
3. Put a dot for each electron in the ______
first energy
level (Max of __
2 ) and then move on to the second if
necessary.
second energy
5. Put a dot for each electron in the _______
8 ) and then move to the third if
level (Max of __
necessary.
6. Repeat for the third level if necessary
Practice: Bohr Models
Li
Draw the Nucleus – make sure it is big enough to write inside
Add the protons and neutrons to the nucleus
Draw the first energy level and put a dot for each electron on that level (Max of 2)
Draw the second energy level and put a dot for each electron on that level (Max of 8)
3p
4n
Notice the yellow
electrons – these
are Valence
Electrons (e- on the
outermost shell)
31
Practice: Bohr Models
Al
Draw the Nucleus – make sure it is big enough to write inside
Add the protons and neutrons to the nucleus
Draw the first energy level and put a dot for each electron on that level (Max of 2)
Draw the second energy level and put a dot for each electron on that level (Max of 8)
Draw the third energy level and put a dot for each electron on that level (Max of 18)
13p
14n
Notice the yellow
electrons – these
are Valence
Electrons (e- on the
outermost shell)
32
Bohr Diagram wkst
33
Draw the Bohr
diagram for an
atom of Aluminum.
Review: Valence Electrons
What are they?
Electrons on the outermost energy level
Why are they important?
They are the only electrons involved in
chemical reactions
How do you know how many an atom has?
On the Periodic table, below the atomic
number
Lewis Dot Diagrams
Electron Dot diagrams, (also called
Lewis Dot diagrams) show only the
______
_________
valence electrons in an atom.
It includes the ______________
element symbol and
number of valence electrons.
the _______
Let’s figure out the ‘rules’ for drawing
Lewis/Electron Dot Diagrams…
Rules - Lewis Dot Diagrams
1. The first __
2 valence electrons go on
top side of the element symbol.
the _____
H
He
Rules - Lewis Dot Diagrams
2. Electrons are added ____
one at a time in
clockwise direction as seen below.
a _________
1
8
5
2
J
7
4
3
6
Practice
39
p=
n=
9
10
Identify the atom above
40
Electron
Movement
Electron Energy
We already learned that electrons are located
levels outside the
energy ______
on specific _______
nucleus
The electrons closer to the nucleus have
absorb energy
lower energy and need to _______
______
to get farther away from the nucleus.
Electron Movement
When you look on the periodic table, you
ground state electron configuration
get the _______
heat or __________
electrical
If exposed to enough _____
absorb energy and
energy, electrons can _______
jump up an energy level and become excited
______.
Electron Movement
temporary and really
The excited state is __________,
drop back down to
quickly the electron will _____
where it came from and give off the energy
it absorbed.
44
Energy Released
Electrons will
release energy as
light
______.
Since each energy level jump has a different
amount
_______ of energy, the energy given off will
color of light.
be a different ______
Normal Light
White light is made of
all the colors of the
____
_________.
spectrum
Passing light through
prism separates the
a ______
light into individual
colors – each
________
having its own
______________.
wavelength
Bright-Line Spectra
Each element gives off different
amounts of energy – this produces a
________
pattern of ______
lines and
unique _______
colors that we call a __________
bright-line
________
n=4
spectrum.
n=3
n=2
n=1
Bright-line Spectra
They are formed
when atoms
emit (give off)
______
energy
__________.
Each element
produces a
unique pattern.
________
Unknown Spectra
49
Flame Test lab
Spectroscopy lab
BELL RINGER
What element is the unknown?
Unknown
Isotopes
element
Isotopes are atoms of the same ________
neutrons
that have different numbers of ________
masses
and therefore different ________.
How many neutrons do
each of the carbon
atoms to the right have?
Isotope Problems
Which of the following are isotopes of each
other?
17
8
O
17
6
C
18
8
18
O
8
N
How many protons and neutrons do the
following have?
37
6
Cl
40
K
Practice
55
Ions
Not
or
protons
Ions have the same number of _______
electrons
but a different number of _________.
charged particle,
This makes an ion a ________
since there aren’t the same number of
protons and _________.
electrons
________
Calculating Charge
Remember: Electrons are negative!
ion has more electrons it is _____!
If the _____
ion has more protons it is _____!
+
If the _____
The charge of the ion is
always written here
-1
Cl
Ion Practice
Figure out the electrons for each of the
following ions
+1
Na
-2
S
+3
Al
-1
F
Practice
59
BELL RINGER
Draw the dot
diagram and Bohr
diagram for Si.
BELL RINGER
Give the p, n, and e for both
isotopes of Cl-35 and Cl-37.
Identify the number of p, n,
and e in an atom of
Fluorine.
62
BELL RINGER
Draw the Bohr diagram
for Sulfur.
BELL RINGER
How are bright lines
produced?
BELL RINGER
How can we identify
elements based upon
flame tests?
BELL RINGER
What is the charge and
location for all three of
the subatomic particles?
BELL RINGER
How do we know
what elements
stars are made of?
Quiz
1. How many valence electrons does
Strontium have?
2. What is the symbol for the element
iron?
3. Draw the Bohr diagram for Chlorine.
Quiz
4. What is the electron configuration for
Arsenic?
5. How many neutrons does Phosphorus
have?
BELL RINGER
Draw the Bohr diagram and
Dot diagram for Boron.
71