Honors College Prep Chemistry
UNIT 3 – ATOMIC STRUCTURE - CHAPTER 4 and 5 – UNIT OVERVIEW
GUIDING QUESTION(S):
? How do chemists (scientists) go about their work?
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How has our model of the atom changed through time?
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What evidence do we have to support our model of the atom?
BIG IDEA(S):
1. Atoms are very small and are made up of subatomic particles.
2. Isotopes are atoms of the same element that differ in their number of neutrons. The existence of isotopes explains
why atomic masses are expressed as decimals rather than whole numbers.
3. Our model of the atom has changed through time to accommodate new evidence.
4. The current model of the atom holds that atoms contain a central nucleus containing protons and neutrons and that
the electrons are distributed around the nucleus, occupying almost all of the volume of the atom.
5. Electron configuration is a way of describing where electrons are in an atom. This information helps us understand
how atoms combine and why the periodic table is such a powerful tool for chemists.
6. Emission spectra of elements are the most compelling evidence to support our current model of the atom.
IMPORTANT VOCABULARY:
Review:
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atom
atomic mass
atomic number
periodic table
Essential:  mass
number
 isotope
Secondary:
 atomic mass
unit (amu)
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electron
proton
neutron
nucleus
 models of the atom, including
indivisible, plum pudding model,
nuclear atom, Bohr model (aka
planetary model), electron cloud
model
 energy levels and sublevels
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wavelength
frequency
energy
electromagnetic radiation (infrared,
visible, ultraviolet)
quantum mechanical model
atomic orbital
electron configuration
ground state
excited state
quantum
photon
emission spectrum
 quantum numbers
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Heisenberg Uncertainty Principle
Aufbau principle
Pauli exclusion principle
Hund’s Rule
IMPORTANT PEOPLE / EVENTS:
Essential:  Democritus
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Secondary:
Dalton
Goldstein/Thomson
Rutherford
Bohr
Schrodinger
Chadwick
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atomic philosophy
atomic theory
plum pudding model
nuclear atom
Bohr model (aka planetary model)
electron cloud / quantum
mechanical model
 no experimental evidence
 ratio of combining elements
 cathode ray experiments: protons, electrons
 gold foil experiment: nucleus
 emission spectra: energy levels
 mathematical analysis
 neutron
Becquerel, Nagaoka, Curie, Roentgen, Mendeleev, Meyer, de Broglie, Einstein, Heisenberg, Aufbau, Pauli, Hund,
Davisson, Germer, Planck
OBJECTIVES:
At the end of this unit, you should be able to…
1. Identify and discuss developments in atomic theory (from early times through modern times)
a)
b)
c)
d)
e)
Describe the significance of models in science. Why are they used and why do they change?
Identify significant people and their contributions to the development of the model of the atom
Identify the major components of Dalton’s atomic theory and recognize what is and isn’t still accepted in the scientific
community
Describe how the model of the atom has changed through time
(Democritus/Dalton’s Model (indivisible sphere), Thomson’s Model (plum pudding), Rutherford’s Model (nuclear atom), Bohr
Model (planetary model), Modern Model (electron cloud / quantum mechanical)
Identify the major components of the Bohr model of the atom and identify what is and isn’t still accepted about this model in
the scientific community
2. Differentiate among major subatomic particles
a)
b)
c)
Identify by name, location, relative charge, relative mass
Given two or more of the following values, determine the others:
atomic number, mass number, number of protons, number of neutrons, number of electrons
Draw a simple Bohr model of an atom of element # 1-20.
3. Define isotope and use your understanding to …
a)
b)
c)
Determine the atomic number and mass number of given isotopes of elements.
Identify the significance of average atomic mass. (Describe why atomic mass is not a whole #?).
Calculate the average atomic mass of a mixture of isotopes of an element and related calculations.
4. Describe the relationship between electromagnetic radiation and an electron
a)
b)
c)
d)
e)
f)
g)
Identify the sequence of different types of electromagnetic radiation (infrared, ROYGBIV, ultraviolet).
Describe how electrons in atoms produce characteristic flame test colors and spectra.
Define quantum / photon.
Differentiate between continuous and bright line emission spectra.
Describe the relationship between wavelength and energy.
Given Plank’s constant, the speed of light, and the wavelength of light given off by a particular element, determine the
difference in energy between the ground and excited state. ( ∆ E = hc/wavelength)
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will require that you be able to do metric conversions (nm  m)
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will require that you be able to work with scientific notation
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will require that you be able to use significant figures
Explain how spectra provide evidence for the modern model of the atom.
5. Describe the modern (aka electron cloud or quantum mechanical) model of the atom
a)
b)
c)
d)
e)
f)
Describe the modern view of the atom.
Characterize the position and velocity of an electron in an atom according to the Heisenberg Uncertainty Principle.
Describe the four quantum numbers that characterize the probably position of an electron: principle (energy level), orbital
(sublevel), orientation, spin
Use the Aufbau principle, the Pauli exclusion principle, Hund’s rule and quantum numbers to describe an electron in an atom.
Determine the electron configurations of the elements or identify elements by their electron configuration
Be comfortable with multiple notations: ‘long’, ‘short’ (with noble gas), ‘fill-in-the-box’ format.
Recognize that even this model of the atom has shortcomings and will likely change in time.
-----------------------------------------------NOTE: You may use ‘gold’ sheets (provided by the teacher) and your calculator* on the test.
[*Calculators with a Periodic Table program will be exchanged for a standard scientific calculator for this test.]
You may ONLY use the time allowed for the class period.
In addition, your teacher may allow the use of additional materials – ask a few days before the test.
How to Prepare for your TEST on Atomic Structure:
(1) Go over this info sheet… topic by topic… make sure you can do what is listed. If you are unsure about
something, refer to your journal and/or text. If that doesn’t help, call a study buddy…. Or see Ms. Smith after
school or during lunch.
(2) Review your journal
Look through the entries for this unit. If you are confident of what you review, great. If you still have questions
about the material, ask questions. Feel free to add additional comments to your journal as you prepare.
(3) Organize and review your folder. Your pocket folder should contain any papers not included in your comp
book. It will not be scored for this unit.