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Atomic Theory
Unit 1
Mr. Marash
At the conclusion of the Unit you will be able to:
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Use models to describe the structure of the atom
Describe scientific experiments and explain how they relate to the structure
of an atom
Determine the number of protons, neutrons and electrons in an atom or an
ion given its mass number
Calculate the mass number given protons and neutrons
Calculate the atomic mass given relative abundance
Determine the most abundant isotope given atomic mass
Distinguish between ground state and excited state based on electron
configuration
Identify an element by comparing bright line spectra to a given spectra
Determine the number of valence and non-valence electrons of an atom given
its electron configurations
Draw Lewis Dot (electron dot) diagrams of atoms and ions
Interpret and write isotopic notation
Compare and contrast the subatomic particles in terms of charge, mass and
location in the atom
Distinguish between chemicals changes and physical changes
Frame of Reference
Activity
Example: Chemistry>
Directions:
1. Use the word Chemistry to
generate at least 4 words or phrases
that relate to Chemistry and write
them in the circles. It can be anything
you know
2. Then in the squares write down
how you know that word or phrase.
Daily Essential Question:____________________________________________________________________
Daily Essential Question:____________________________________________________________________
What Makes up an atom??
Read Pages 113-114, starting with “The proton and the neutron” and answer the
following questions
1. Compare and contrast a proton and a neutron, in terms of charge and mass
(mention both charge and mass in your answer).
___________________________________________________________
___________________________________________________________
___________________________________________________________
2. Compared to a proton, an electron has
a) the same charge and mass
b) the opposite charge and the same mass
c) the opposite charge and less mass
d) the opposite charge and greater mass
3. Which statement best describes the nucleus?
a) it contains most of the mass of the atom and occupies the most
volume of the atom
b) it contains most of the mass of the atom, but occupies a small
percentage of the volume of the atom
c) it contains a small percentage of the mass of the atom and
occupies a small percentage of the volume of the atom
d) it contains a small percentage of the mass of an atom, but occupies
the most volume of the atom.
Cite evidence from the text to support your answer for #3.
4.
___________________________________________________________
___________________________________________________________
___________________________________________________________
5. Draw a model (diagram) of
the atom. Label nucleus, proton,
neutron, and electron cloud
6. What did you learn from this
reading that you did not know before?
Daily Essential Question:____________________________________________________________________
What Makes up an atom??
I.
Structure of an Atom
A. What is an Atom
i.
ii.
iii.
B. Subatomic Particles (Table O in reference Table)
Particle
Proton
Neutron
Electron
Symbol
Charge
Mass
Location
Daily Essential Question:____________________________________________________________________
As time elapsed, how did the model of the atom evolve?
II.
The History of Atomic Theory
The word atom comes from the Latin words ATOMOS
(TRANSLATION ___________________________________________________________________)
A. Dalton-1803 (Reference: Textbook p. 104-105)
1. Experimental Evidence
Law of
Conservation of
Mass
Law of Definite
Properties
Law of Multiple
Proportions
2. What were the conclusions of Dalton’s Experiments?
3. What is Dalton’s Model of the Atom?
a.
b.
c.
4. Picture of Dalton’s Model
Solid Sphere (Kinda like a marble)
Daily Essential Question:____________________________________________________________________
As time elapsed, how did the model of the atom evolve?
B. J.J. Thomspon- 1897 (Textbook p. 107-110)
1. Cathode Ray Experiment
2. Experimental evidence
a
b
3. What were the conclusions of Thompson’s Experiment?
a.
b.
4. The PLUM PUDDING MODEL (or Yogurt and Granola)
a.
b.
5. Picture of Thompson’s Model
Daily Essential Question:____________________________________________________________________
As time elapsed, how did the model of the atom evolve?
C. Ernest Rutherford – 1909 (Textbook p. 111-113)
1. The Gold Foil Experiment- Rutherford shot alpha particles, which
are positively (+) charged, at a sheet of gold foil.
2. Experimental Evidence
a
b
3. If you shot positive particles at atoms and only some were deflected what
conclusion would you make? Make your prediction below.
(Hint: Opposites attract)
4. What did Rutherford’s model look like?
a.
b.
c.
5. Draw the Rutherford model
As time elapsed, how did the model of the atom evolve?
Daily Essential Question:____________________________________________________________________
D. Niels Bohr – 1913 (Textbook p. 146-148)
1. Analyzed _____________________________ of hydrogen
a. Emission Spectra is _____________________________________________
2. Experiment Evidence
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3. How could this happen?
(Conclusions)
a.
b.
4. What did Bohr’s model look like?
a.
b.
c.
5. Picture of The Bohr Model
6. Practice Regents Questions
Daily Essential Question:____________________________________________________________________
1. Which of the following did Rutherford’s
Gold Foil experiment prove?
4. According to the Wave-Mechanical Model,
a. That the atom was a uniformly dense
sphere.
a. electrons are found in areas of high
probability called orbitals
b. That the atom is mostly empty space
with a dense, positive core.
b. electrons travel around the nucleus in
circular paths called orbits
c. That most the atom consists of a
uniform positive “pudding” with small
negative particles called electrons
embedded throughout.
c. electrons are found in areas of high
probability called orbits
d. That electrons travel around the
nucleus in well-defined paths called
orbits.
2. J.J. Thomson’s Cathode Ray Tube
experiment led to the discovery of
a. the positively charged subatomic
particle called the electron
b. the positively charged subatomic
particle called the proton
c. the positively charged subatomic
particle called the electron
d. the negatively charged subatomic
particle called the electron
d. electrons travel around the nucleus in
random paths called orbitals
5. Which of the following does not follow
Dalton’s Postulates?
a. All atoms of a given element are
identical
b. All atoms look like a simple sphere
c. Compounds are formed by
combinations of 2 or more different
elements
d. Atoms of different elements have
different properties and masses
6. When electrons in an atom gain or absorb
enough energy, they can
a. jump to the ground state
3. According to the Bohr Model,
a. electrons are found in areas of high
probability called orbitals
b. electrons travel around the nucleus in
circular paths called orbits
c. electrons are found in areas of high
probability called orbits
d. electrons travel around the nucleus in
random paths called orbitals
b. fall back to the ground state
c. jump to an excited state
d. fall back to an excited state
7. When excited electrons lose or emit enough
energy, they can
a. jump to the ground state
b. fall back to the ground state
c. jump to an excited state
d. fall back to an excited state
How do I Differentiate Between Atoms?
Daily Essential Question:____________________________________________________________________
III.
Atomic Number and Mass Number
a. Atomic Number
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X
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QUESTION: How many protons are in the following atoms?
Oxygen (O) Cholrine (Cl) Calcium (Ca) Mercury (Hg)
QUESTION: Which element has:
15 protons
25 protons
38 protons
82 protons
b. Mass Number
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X
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How do I Differentiate Between Atoms?
Reminder to
yourself: How
do you figure
this out?
Daily Essential Question:____________________________________________________________________
QUESTION: How many protons, neutrons and electrons are in the
following?
55Fe
Element
Sodium-23
P-31
*** Take
note of the
different
notations
used to
represent an
element***
Proton Count
Neutron Count
Electron Count
Putting it all together
For the following symbols, identify the number of p,n,e, atomic number,
mass number and element symbol.
Symbol
Protons Neutrons Electrons Atomic # Mass # Element
7
3𝑋
2
1𝑋
79
32𝑋
Different Forms of Elements
Daily Essential Question:____________________________________________________________________
IV.
Isotopes
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 Example
Element
12C
Proton Count
13C
14C
What two things stay
the same for isotopes?
Neutron Count
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Electron Count
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V.
Atomic Mass
A.
B.
QUESTIONS:
1. If there exists 25% of Cl-37 and 75% of Cl-35 what is the atomic mass
of chlorine?
2. Copper has two isotopes, Cu-63 and Cu-65. There is 69.2% copper-63
and 30.8% copper 65. What is the atomic mass of copper?
Different Forms of Elements
Daily Essential Question:____________________________________________________________________
3. Atomic mass can also be identified as the MOST ABUNDANT isotope.
a. Which isotope is more abundant Na-22 or Na-23?
b. Hydrogen has three isotopes, H-1, H-2 and H-3. Which one is
most abundant?
VI.
Ions
1.
A.
B.
C.
2.
QUESTIONS: Fill in the table below
Daily Essential Question:____________________________________________________________________
Element
Protons
Electrons
Na+
ClMg2+
S2Write the symbols for an ion with
9p and 10 e _______________________
13p and 10 e_____________________
24p and 21 e______________________
7p and 10 e_______________________
What is the charge on a magnesium ion that has lost two electrons? _______
What is the charge on a fluoride ion that has gained one electron? _______
Give the correct chemical symbol for the ion formed when oxygen gains 2 electrons: _______
Give the correct chemical symbol for the ion formed when sodium loses one electron: _______
Back to the Bohr-Ring Model
Daily Essential Question:____________________________________________________________________
Warm-up:
How did Bohr improve upon Rutherford’s Atomic model? Look back in your
notes if you need to.
VII.
Energy Levels
A.
B.
Energy Level (n)
n=
Number of electrons
1
n=
n=
n=
C.
n=
D.
What Happens when Electrons Change Energy Levels?
Daily Essential Question:____________________________________________________________________
VIII.
Electron configuration
A. Ground State of atomsExamples:
B. Ground State of ions-
Na
Ge
Au
Ar
O
Fe
Examples:
C.
Na+
Cl-
Se2-
Sr2+
Rb+
O2D. How can you tell the if the electron configuration is for
ground state or excited state?
Questions:
2-1:_____________________
2-8-2:___________________
2-0-1:___________________
2-8-8-2:_________________
2-7-3:___________________
2-8-17-6:________________
IX.
Bohr Models-
Daily Essential Question:____________________________________________________________________
C. Bohr Diagrams –
1. Look up electron configuration of
element (if you are working with
an ion, add/subtract the proper
amount of electrons from outer
shell of configuration)
2. Draw nucleus (with a square) and
write correct number of protons
and neutrons inside.
3. Using rings or shells, place the
proper number of orbits around
your nucleus.
4. Using either an “x” or a dot to
represent your electrons,
place the correct number of
electrons in the area that
would correspond to the
number 12 on the face of a
clock in the orbit closest to
the nucleus only.
5. Place one “x” or one dot at a
time around your 2nd orbit in
the areas that would
correspond to the numbers
12, 3, 6, and 9 on the face of a
clock.
6. If there are any electrons
remaining in your
configuration, pair them up
with electrons you have
already placed.
Questions/Practice:
Carbon
e- configuration_____________ F-
e- configuration____________
Daily Essential Question:____________________________________________________________________
Na+
e- configuration_____________
Ar
e- configuration_____________
Al
e- configuration_____________ S2-
e- configuration______________
X.
Lewis Dot Diagrams
Daily Essential Question:____________________________________________________________________
A. Valance Electrons-
Examples: Mg ________________
C__________________
B. Lewis Dot Diagrams-
Steps to Draw a Lewis Dot Diagram
1. Write the element’s symbol
2. Retrieve electron configuration from
Periodic Table. The last number in the
configuration is the___________________________
3. Using either an “x” or a dot to represent
your electrons, place that many electrons
in the next orbit in the areas that would
correspond to the numbers 12, 3, 6, and 9
on the face of a clock.
4.If you are working with an ION you must
adjust the valence electrons (add or
subtract electrons) in the configuration
before constructing your Dot Diagram.
Your final diagram must include
brackets and the charge on the ion.
Practice:
Daily Essential Question:____________________________________________________________________
Argon
Nitrogen
N3-
Oxygen
Silicon
Sodium
Na+1
O2-
1. What is the advantage to using the Bohr model as opposed to the Lewis model?
a. The Bohr model provides more information than the Lewis model.
b. The Bohr model is less bulky than the Lewis model.
c. The Bohr model shows the valence electrons.
d. The Bohr model shows how many bonds atoms of an element can form.
2. What is the advantage to using the Lewis model as opposed to the Bohr model?
a. The Lewis model provides more information than the Bohr model.
b. The Lewis model is less bulky than the Bohr model.
c. The Lewis model shows the valence electrons.
d. The Lewis model shows how many bonds atoms of an element can form.
3. What is the maximum number of electrons an atom or an ion can have in its
valence shell?
a. 2
c. 6
b. 4
4. 8
XI.
Physical and Chemical Changes
Daily Essential Question:____________________________________________________________________
A. Physical and Chemical Properties
1. Physical properties —
a. Intensive property
Examples:
b. Extensive property –
Examples:
2. Chemical properties —
Examples:
B. Physical and Chemical Changes
1. Physical change –
Examples:
2. Chemical change –
Daily Essential Question:____________________________________________________________________
Example:
3. Four signs of a possible chemical change
a.
b.
c.
d.
A precipitate is
Daily Essential Question:____________________________________________________________________
Vocab review:
Atomic mass
Atomic mass
unit
Atomic
Number
Atomic
Radius
Bohr’s model
Bright-line/
Emission
Spectra
Cathode ray
Chemical
Change
Chemical
Property
Dalton’s
Model
Electron
Electron
Configuration
Energy level
Excited state
Gold foil
Experiment
Ground state
Ion
Isotope
Lewis dot
Diagram
Mass number
Neutron
Daily Essential Question:____________________________________________________________________
Nucleus
Nucleon
Orbital
Physical
Change
Physical
Property
Proton
Rutherford’s
Model
Subatomic
Particles
Thomson’s
Model
Valence
Electron
WaveMechanical
Model