Name:
Period:
Chemistry Unit 2 – Atomic Structure
Matter has definite structure that determines characteristic physical and chemical properties: Apply an understanding
of atomic and molecular structure to explain the properties of matter, and predict outcomes of chemical reactions.
Chemistry Daily Journal
What do I need to accomplish
today?
Today’s Date
What do I need to finish up at
tonight at home?
Chemistry Course Objectives:
1. Count the number of protons, neutrons, and electrons in any given isotope (DOK 1-3).
2. Calculate the average atomic mass for an element with more than one isotope (DOK 2-3).
3. Justify modifications to a scientific theory when new evidence is discovered (DOK 1-3).
Objective
Learning Opportunities
Due
Date
□ Podcast 3.1 Basic Atomic Structure
2.1 Describe the
number and type of
subatomic particles in
an atom
2.2 Recognize
contributions various
scientists have made
to the development of
modern atomic theory
2.3 Calculate mass
number and average
atomic mass
Unit 2 Test
□
□
Read p. 101-112, answer p. 112, 17-18
Drawing and making atom-The Fruity Pebbles Lab
□
BioPoem – Introduction to a Scientist
□ Atomic Structure
Podcast: What is Matter Made Of
Podcast: Discovering the Electron
□ Podcast: Discovering the Nucleus
□ Models of the Hydrogen Atom-PhET Simulation
08/29
□
□
09/02
□ Atomic Structure Quiz
□
□
□
□
□
Podcast 3.3 Isotopes
Read p. 112 – 117, answer p. 113, 19-20; p. 117, 23-24
□
Unit 2 Review and Test
Isotopes and Average Atomic Mass
Beanium Lab
Quiz on Atomic Structure and Isotopes
09/05
09/09
SCALE: Structure of the Atom
4 – SWBAT Differentiate between isotopes of the same element, ions and/or atoms of different elements to
identify atomic number, mass number, and the numbers of protons, neutrons, and electrons using both
symbols and models. Given graphical data about isotopes, analyze the average atomic mass for any given
element. Examples:
128
2−
52𝑇𝑒
3 – SWBAT Differentiate between isotopes of the same element and/or atoms of different elements to
identify atomic number, mass number, and the numbers of protons, neutrons, and electrons using both
symbols and models. Given data
about isotopes, analyze the
average atomic mass for any
given element.
Examples:
89
39𝑌
2 – SWBAT Using mass number and atomic number, give the number of protons, electrons, and neutrons in
isotopes and/or atoms. Given data about 3 or fewer isotopes, calculate the average atomic mass for any
given element.
1 – SWBAT With help, Ss are able to use mass
number and atomic number to determine the
number of protons, electrons, and neutrons in
isotopes and/or atoms. Given data about 2 or 3
isotopes, calculate the average atomic mass for
any given element.
0 – Even with help, Ss are not able to use mass
number and atomic number to determine the
number of protons, electrons, and neutrons in
isotopes and/or atoms. Given data about 2 or 3
isotopes, calculate the average atomic mass for
any given element.
SCALE: Modifications to the Atomic Theory
4 – Justify the modifications to atomic theory by evaluating implications of each of the historical
experiments that led to our current understanding of atomic structure, including but not limited to: John
Dalton, Antoine LaVoisier, JJ Thomson, Ernst Rutherford, Max Planck, Niels Bohr, Louis DeBroglie, and
Erwin Schroedinger.
3 - Using a variety of experimental data, explain how and why our ideas of relative size, charge, and location
of protons, neutrons and electrons have been modified from the ancient Greeks to the Bohr Model.
2 – Describe how ideas of relative size, charge, and location of protons, neutrons and electrons change
because of the Plum Pudding Model, the Gold Foil Experiment, and the Bohr Model.
1 – With help, Ss can describe how ideas of relative size, charge, and location of protons, neutrons and
electrons change because of the Plum Pudding Model, the Gold Foil Experiment, and the Bohr Model.
0 - With help, Ss are not able to describe how ideas of relative size, charge, and location of protons,
neutrons and electrons change because of the Plum Pudding Model, the Gold Foil Experiment, and the Bohr
Model.
Drawing and Making Atoms – The Fruity Pebbles Lab
Purpose: To use information from the periodic table to draw box and Bohr representations of atoms.
Materials: Periodic Table, pencil, paper, cereal
Procedure:
1. Use your periodic table to determine the name of the element.
2. The atomic number indicates the # of protons in the nucleus. It also gives the number of electrons in a
neutral atom.
3. The atomic mass gives the # of protons plus the average # of neutrons in the nucleus. (Ex: Round atomic
mass to nearest number, then subtract that by the atomic number to get the number of neutrons in the
nucleus)
4. Remember that electrons exist in energy levels around the nucleus. The 1st energy level holds 2 electrons,
2nd level holds 8, and 3rd level holds 8.
Box Diagram example of Argon:
18
Represents atomic #
2
Ar
Represents atomic mass
Represents electron
energy levels
8
8
Represents atomic symbol
39.948
Ar
From the information in the periodic table you can create a 2-D model of what an atom looks like called the Bohr
model. This model shows the nucleus with the protons and neutrons, and it shows energy levels with electrons.
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+
+
+
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++
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What element is this?
+
_
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Fill in the box with the
correct information.
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________________________________________________________________________________________________________________________
Oxygen:
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Drawing:
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Hydrogen:
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Nitrogen:
____
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Carbon:
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Drawing:
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Chlorine:
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Drawing:
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Extra Credit:
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Magnesium:
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Sodium:
Drawing:
Aluminum:
Drawing:
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Sulfur:
____
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Boron:
Drawing:
PhET Simulation Exploration – Models of the Hydrogen Atom
http://phet.colorado.edu/simulations/sims.php?sim=Models_of_the_Hydrogen_Atom
Overview
One of the most tantalizing puzzles at the beginning of the 1900s for scientists was to describe the
make-up of the atom. As I explained in class, light was used to investigate the make-up of the atom.
In this activity, you will first observe a simulated light spectrum of hydrogen gas. This is the same
spectrum that you observed in class. You will then look at spectra predicted by different models of
the atom. The models you will test include:





John Dalton’s Billiard Ball model
J.J. Thomson’s Plum Pudding model
Ernest Rutherford’s Classical Solar System model
Niels Bohr’s Shell model
Louis deBroglie’s Electron Wave model
Procedure and questions
1. Explain why, with white light, the light photons passing up through the box have different
colors.
2. Decide how you can distinguish between UV and IR photons. Record that information below.
3. Watch the photons carefully. Most of the light gun photons pass through the box of hydrogen
unaffected. Occasionally a photon is absorbed by something in the ? box and a new photon of
the same energy (color) leaves the box. Describe what is going on in the ? box.
4. Describe what is happening to the spectrum below. Include in your description the colors,
estimated wavelengths, and relative numbers of stacked colored balls. These colored balls
correspond to photons emitted by the ? box.
5. John Dalton proposed that an atom was simply a very tiny hard ball. To see this simulated,
in the top left corner, switch from Experiment to Predict and highlight the Billiard Ball
model.
Describe what is happening below.
6. Below, sketch your idea of what the spectrum will look like for Dalton’s model.
7. Does the spectrum for the Billiard Ball model match that of the experimental (real)
hydrogen spectrum?
8. Switch to Thomson’s Plum Pudding model, describe what is happening within the atom
below.
9. Compare the Spectrometer snapshot of the Plum Pudding model to the Experiment. Does
the spectrum for the Plum Pudding model match that of the real hydrogen spectrum?
10. Just for fun, switch to the Classical Solar System model. This was Rutherford’s model that
assumes the atom is like our solar system. Describe what happens below.
11. Switch to the Bohr model. Describe what you see in the atom diagram.
12. Describe what you see in the energy level diagram
13. Describe how the atom diagram and energy level diagrams are related.
14. Click on the Spectrometer camera to take a snapshot of the Bohr model. Compare the
snapshot of the Spectrometer of the Bohr model to the Experiment. How well does the
Bohr Shell model spectrum match the experimental (real) hydrogen spectrum? Explain in
detail.
Luis de Broglie was the first atomic theorist to incorporate the ideas of Planck and Einstein that
electrons can be both waves and particles. He developed the de Broglie hypothesis stating that any
moving particle or object had an associated wave (wave-particle duality). De Broglie thus created a
new field in physics called wave mechanics, uniting the physics of light and matter. For this he won the
Nobel Prize in Physics in 1929. Among the applications of this work has been the development of
electron microscopes.
15. Describe what is the same and different about the de Broglie and Bohr models of the
hydrogen atom.
16. Compare the deBroglie Spectrometer to the Experiment. How well does the de Broglie
Electron Wave model spectrum match the real hydrogen spectrum?
17. Describe what you see in the 3-D view.
Atomic Mass of Beanium
Purpose : To calculate the average atomic mass of the new element Beanium.
Materials: Three or four different samples of beans, balance, pencil, and laboratory record sheet
and weighing dishes.
Procedure:
1) Obtain the sample of Beanium.
2) Separate the 3 or 4 isotopes (white beans, kidney beans, and brown beans etc) and count
how many of each are present. Record this number on your data table below.
3) Measure the mass of each isotope as a group (each bean type is an isotope of the element
Beanium). Record the data on your data table.
4) Fill in the rest of the information in the table according to the direction given in analysis
section below.
DataTable
Kidney beans
1) Total mass
2) Number
3) Average
mass (g)
4) Percent
abundance
5) Relative
abundance
6) Relative
mass
White beans
Brown beans
Totals
Analysis: Using the experimental data, record the answers to the following questions.
1) Calculate the average mass of each isotope by dividing its total mass by the number of particles
of that isotope. Record your data in the table.
2) Calculate the percent abundance of each isotope by dividing its number of particles by the total
number of particles and multiplying by 100.
3) Calculate the relative abundance of each isotope by dividing the percent abundance from step 2
by 100.
4) Calculate the relative mass of each isotope by multiplying its relative abundance from step 3 by
its average mass.
5) Calculate the atomic mass of all Beanium particles by adding the relative masses. This average
mass is the average atomic mass of Beanium.
6) Explain the difference between percent abundance and relative abundance. What is the result
when you total the a) individual percent abundances? And b) the individual relative
abundances?
7) The percent abundance of each kind of bean tells you how many of each kind of bean there are in
every 100 particles. What does relative abundance tell you?
8) Compare the total values for Rows 3 and 6 in the table. Why can’t the atomic mass in Row 6 be
calculated the way the total for Row 3 is calculated?
9) Explain any difference between the atomic mass of your Beanium sample and that of your
neighbor. Explain why the difference would be smaller if larger samples were used.
Unit Two Review Questions
1. Match the following historical experiments with the significance of their results.
___ Ancient Greeks and philosophy
A. Discovery of the small positively charged nucleus
___ 4 Tenants and Billiard Ball Model
B. Discovery of the electron
Determined that electrons were located in energy
___ Cathode Ray Tube Experiments and
C.
Plum Pudding Model
levels.
Proposed the first idea of the atom in the 4th
___ Gold Foil Experiment
D.
century BC.
___ The Photoelectric Effect and Bohr
E. Proposed first modern version of the atomic theory
Model
2. Complete the table for the following elements.
Element
Isotope
Atomic
Mass
# of
# of
# of
Hyphen
or Ion
Notation Number Number Protons Electrons Neutrons Notation
Manganese
25
30
(Mn)
Na-23
Sodium
(Na)
9
10
Bromine
(Br)
35
45
Barium
Yttrium
(Y)
81
89
39𝑌
Arsenic
(As)
75
33
24
24
227
28
89
3. A sample of hydrogen is 99% 1H, 0.8% 2H, and 0.2% 3H. What is its average atomic mass?
16. Write the isotope notation of the ion with 29 p+’s and 27e-’s.
17. Write the Isotope Notation for the ion with 27 p+’s , 32 no, and 25 e-’s.
18. How many protons, neutrons, and electrons are in 59Ni+2?
19. How many protons, neutrons, and electrons are in 140Ce+3?