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Which scientist is credited with the discovery of
electrons by experimenting with Cathode Ray Tubes?
Atomic Structure
Notes
3
Atomic Structure
Subatomic particles include ________, _________ and _________.
protons neutronselectrons________ and
_________ are inside the ________
Protons neutronsnucleus
__________ are found __________ the nucleus
Electronsoutside
Atoms are made up of __________ _________ .
subatomic
particles
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Subatomic Particles
Protons have a _________ charge and a mass of ________.
Neutrons have a _________ charge and a mass of _________.
Electrons have a _________ charge and a mass that is so ______ that we consider electrons to have ____ mass!
+1 AMU
neutral1 AMU
-small
“NO”
1 AMU = Atomic Mass Unit
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Number of Protons
Elements in the Periodic Table are organized by ________ ________.Atomic number
The atomic number is the same as the number of ________.protons
Every element has a _________ number of protons, and therefore a ________ atomic number.
different
different
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Atomic Number = # protons
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Number of Electrons
In a _________ atom, the number of
_________ always equals the number of
__________.
neutral
protons
electrons
#p = #e
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Electron PracticeFind the number of protons and electrons in the following atoms:
Symbol Protons Electrons
Mg
O
Au
Ti
12 12
8 8
79 79
22 22
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Atomic Mass
Proton = ________ amu1
An atom’s mass is the sum of its parts
Electron = ________ amu
Neutron = ________ amu1
0
Since the electron has practically no mass we don’t count it in the mass of the
atom
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Atomic Mass
You can find the mass of an atom from
the __________ _______Periodic
For us, that mass is the sum of the
__________ and __________ .Protons
Table
Neutrons
Fluorine has - __________ protons
__________ neutrons
9
19
11
Atomic Mass = # protons + # neutrons
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Number of Neutrons
To get the number of neutrons, get the
atomic mass from the _________ ______
and subtract from that the number of
________.
Periodic
#neutrons = Atomic Mass - #p
Table
protons
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Neutron PracticeFind the number of p, n and e in the
following atoms:
Symbol Protons Neutrons Electrons
Na
B
H
C
11 11
5 5
1 1
6 66
0
6
12
14
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Atomic Structure wkstTextbook Packet
16
How many neutrons does a lead atom have?
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Qz: Atomic Structure
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Element Symbols
Every element has a _________ on the
Periodic Table.
symbol
The symbol is either 1 or 2 letters,
where the first is always a _________
letter, and the second is always a
_______ letter…
CAPITAL
small
H He C Ca
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Element Notation
Element symbols contain the atomic number, mass number and element
symbol.
J Massnumber
Atomicnumber
Element symbol
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Element Notation
Complete the notation for the following:
K Al19
39
13
27
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Atomic Structure wkstTextbook Packet
coninued
22
Identify the atom that has 26 neutrons, 22 protons
and 22 electrons.
BELL RINGER
Draw the electron dot diagrams for
Chlorine and Sodium.
BELL RINGERHow many electrons does a phosphorus
atom have?
Neutrons?
BELL RINGER
Draw the Bohr diagrams for Lithium and
Oxygen.
The Bohr Model
The ________ is in the center of the atom
and contains both _________ and
__________, and the ___________ are found
orbiting the nucleus.
nucleus
protons
neutronselectrons
Basic Layout
Electron Energy Levels
• Electrons are found in _______ levels
around the nucleus.
energy
• The _______ to the nucleus, the ________
the energy of the electrons.
closer lower
• The _______ from the nucleus, the
________ the energy of the electrons.
farther
higher
Electron Configuration
Electron configuration is the ___________ of
electrons outside the nucleus of an atom.
arrangement
The 1st energy level holds up to
____ electrons.
82nd level holds up to ___
3rd level holds up to ___18
2
Electron ConfigurationYou 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 are ___ electrons in the 1st level and ___ electrons in the 2nd level.
2
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How to: Bohr ModelsRules
1. Put the number of _______ in the ________protons nucleus
2. Put the number of _________ in the ________neutrons nucleus
3. Put a dot for each electron in the ______ energy level (Max of __ ) and then move on to the second if necessary.
5. Put a dot for each electron in the _______ energy level (Max of __ ) and then move to the third if necessary.
first2
8second
6. Repeat for the third level if necessary
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Practice: Bohr ModelsDraw the Nucleus – make sure it is big enough to write inside
Add the protons and neutrons to the nucleus
3p4n
Draw the first energy level and put a dot for each electron on that level (Max of 2)
Li
Draw the second energy level and put a dot for each electron on that level (Max of 8)
Notice the yellow electrons – these are Valence Electrons (e- on the outermost shell)
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Practice: Bohr ModelsDraw the Nucleus – make sure it is big enough to write inside
Add the protons and neutrons to the nucleus
13p14n
Draw the first energy level and put a dot for each electron on that level (Max of 2)
Al
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)
Notice the yellow electrons – these are Valence Electrons (e- on the outermost shell)
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Bohr Diagram wkst
Draw the Bohr diagram for an
atom of Aluminum.
What are they?
Why are they important?
Review: Valence Electrons
Electrons on the outermost energy level
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
Electron Dot diagrams, (also called ______ Dot diagrams) show only the _________ electrons in an atom.Lewisvalence
It includes the ______________ and the _______ of valence electrons.
element symbolnumber
Let’s figure out the ‘rules’ for drawing Lewis/Electron Dot Diagrams…
Lewis Dot Diagrams
1. The first __ valence electrons go on the _____ side of the element symbol.
2top
H He
Rules - Lewis Dot Diagrams
2. Electrons are added ____ at a time in a _________ direction as seen below.
oneclockwise
J1 2
Rules - Lewis Dot Diagrams
3
4
5 6
7
8
39
Practice
40
p=
n=
9
10
Identify the atom above
Electron Movement
We already learned that electrons are
located on specific _______ ______
outside the nucleus
The electrons closer to the nucleus
have ______ energy and need to
_______ energy to get farther away
from the nucleus.
lower absorb
Electron Energy
energy
levels
Electron Movement
When you look on the periodic table, you get the _______ state electron configuration
ground
If exposed to enough _____ or __________ energy, electrons can _______ energy and jump up an energy level and become ______.
heat
electricalabsor
b excited
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The excited state is __________, and
really quickly the electron will _____
back down to where it came from
and give off the energy it absorbed.
Electron Movement
temporary
drop
THINK OF A YOUNG KID AFTER EATING CANDY!
Electrons will
release energy
as ______.
Since each energy level jump has a
different _______ of energy, the
energy given off will be a different
______ of light.
light
amount colo
r
Energy Released
Normal LightWhite light is made of ____ the colors of the _________.
allspectrum
Passing light through a ______ separates the light into individual ________ – each having its own ______________.
prism
colors
wavelength
Bright-Line SpectraEach element gives off different ________ of energy – this produces a unique _______ of ______ and ________ that we call a __________ spectrum.
amountspattern lines
colors bright-line
n = 3n = 4
n = 2
n = 1
Bright-line Spectra
They are formed when atoms ______ (give off) __________.
emitenergy
Each element produces a ________ pattern.unique
Flame Test lab
Spectroscopy lab
BELL RINGER
Unknown
What element is the unknown?
IsotopesIsotopes are atoms of the same ________ that have different numbers of ________ and therefore different ________.
elementneutrons
masses
How many neutrons do each of the carbon atoms to the right have?
Isotope ProblemsWhich of the following are isotopes of each other?
O17
8 C17
6 O18
8 N18
8
How many protons and neutrons do the following have?
Cl37
6K40
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Practice
Ions
Ions have the same number of _______ but a different number of _________.
protonselectrons
This makes an ion a ________ particle, since there aren’t the same number of ________ and _________.
charged
protons electrons
Not or
Calculating ChargeRemember: Electrons are negative!
The charge of the ion is always written here
If the _____ has more electrons it is _____!
Cl-1
If the _____ has more protons it is _____!
ion
ion
-+
Ion Practice
Figure out the electrons for each of the following ions
Na+1 S-2 Al+3 F-1
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Practice
BELL RINGER
Draw the dot diagram and Bohr
diagram for Si.
BELL RINGERGive the p, n, and e for both isotopes of Cl-35
and Cl-37.
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Identify the number of p, n, and e in an atom of
Fluorine.
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?
Quiz1.How many valence electrons does
Strontium have?
2.What is the symbol for the element iron?
3.Draw the Bohr diagram for Chlorine.
Quiz4.What is the electron configuration
for Arsenic?
5.How many neutrons does Phosphorus have?
BELL RINGERDraw the Bohr diagram
and Dot diagram for Boron.
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