Download Notes on Chemistry - Properties of Atoms

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Atoms, Ions, and Isotopes
Oh my!
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
http://www.projectsharetexas.org/sites/default/files/resourc
es/documents/EvolutionOfAtomicModel.pdf
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Name that component!
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Has a negative charge
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Has a positive charge
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Has no charge
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Has a relative mass (to proton) of 1
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Has an actual mass of 1.67x10-24
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Has an actual mass of 9.11 x 10-28
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Objectives for Today
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Characterize protons, neutrons, electrons by location, relative
charge, relative mass (p=1, n=1, e=1/2000).
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• Use symbols: A= mass number, Z=atomic number
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• Use notation for writing isotope symbols:235 92 or U-235
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• Identify isotope using mass number and atomic number and
relate to number of protons, neutrons and electrons.
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• Differentiate average atomic mass of an element from the
actual isotopic mass and mass number of specific isotopes. (Use
example calculations to determine average atomic mass of
atoms from relative abundance and actual isotopic mass to
develop understanding)
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How will we do that?
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Group read and presentation
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Everyone takes notes on presentation
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I recap anything necessary
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Significant Figures and Scientific Notation
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Introduce Electron shells
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Discuss Uranium and the nuclear bomb
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Elements on the periodic table
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Elements
 Distinguished
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
Atomic number correlates with number of protons
Therefore an atom is defined by its number of protons
 Therefore an atom is unique by its positive charged
elements
 Have
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a variable mass
Number of neutrons can change (will get into this more
later)
 Have
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by atomic number
a variable charge
Number of neutrons can change (ibid.)
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Calculating things with elements
The
number of neutrons in an atom is
the difference between the mass
number and atomic number
#
of Neutrons = Mass # - atomic #
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Isotopes
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Atoms with the same number of protons but different number
of neutrons
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Therefore, mass changes, charge changes
Hydrogen isotopes
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Hydrogen – 1 (Hydrogen)
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Hydrogen – 2 (deuterium)
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Hydrogen – 3 (tritium)
What happens when we add a fourth neutron?
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Atomic Mass Units
Reference
Isotope is Carbon – 12
Has
six protons, six neutrons and one
amu is equal to
Mass
of carbon-12 divided by 12
(presumably an approximation of the
mass of a proton or neutron)
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Overall amu
To
calculate the atomic mass
of an element, multiply the
mass of each isotope by its
natural abundance, expressed
as a decimal and then add the
products
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Groups
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Difference between atomic number and mass number
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Isotopes
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Atomic mass unit and natural abundance
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Preview of periodic table
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Catalyst 9/16
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Collect one of each handout on table
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Hole punch them if you need to
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Then be seated by the time the bell rings.
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Objectives
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Understand what an ion is
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Analyze diagrams related to the Bohr model of the hydrogen
atom in terms of allowed, discrete energy levels in the
emission spectrum.
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• Describe the electron cloud of the atom in terms of a
probability model.
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• Relate the electron configurations of atoms to the Bohr and
electron cloud models.
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Become familiar with the math of science
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To accomplish these we will
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Take some notes
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Do a demonstration
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Complete several work sheets on the science of math
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https://www.youtube.com/watch?v=WWc3k2723IM
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https://www.youtube.com/watch?v=thnDxFdkzZs
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Then Carbon as an example
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Bohr Model
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Probability Model
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Describes the areas around the nucleus in which we are
likely to find the electrons, depending on their energy level
and element.
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Activity
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Catalyst 9/17
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Review:
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Name the properties (relative mass, charge, location) of an
electron, proton, and neutron
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What happens when the number of protons changes?
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Neutrons?
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Electrons?
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The atomic mass listed on the periodic table is the average
atomic mass. In order to calculate it, we need to know what
isotopes exist, and their natural abundance. Use words or a
formula to state how we calculate average atomic mass
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What are some difference between the Bohr Model and the
Electron Cloud (Probability Model)?
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But first, let me talk about ions
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https://www.youtube.com/watch?v=WWc3k2723IM
 Don’t
overthink this:
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Se refers to an ion with a
positive 3 charge
Therefore
is missing 3 electrons
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Electron Configurations
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Bohr model indicates seven energy levels
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Electron Cloud/Probability Model indicates seven levels, but
up to (and maybe more) four sublevels
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These are s, p, d, f
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They look pretty crazy
You need to know 3 principles of calculating
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Aufbau Principle
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Pauli Exclusion Principle
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Hund’s Rule
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Aufbau
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Electrons fill lowest available energy shells first
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S then p then d then f, until the third orbital
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3
4s happens before 3d
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Pauli Exclusion Principle
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Each orbital can contain two electrons
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Each electron has a positive or negative spin
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These are written as  and 
Pauli Exclusion Principle
Electrons first fill every available empty orbital before taking
a negative spin next to a positive electron
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Quanta
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A unit of energy
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When energy is applied to an atom, the electrons move from
a lower/ground state to an excited state
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When energy is released from the atom, an electron goes
back down to ground state and the energy takes the form of
EM wave discharge
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Significant Figures
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http://www.usca.edu/chemistry/genchem/sigfig.htm
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Catalyst 9/24
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Please take one sheet of paper. Keep it face down. We’ll get
to it later
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There are a number of different articles; yours may not be the
same as your neighbors. That’s fine.
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Actually, it’s not that fine. You shouldn’t know what your
neighbor has because you shouldn’t have turned it over.
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After announcements we’ll have a few test questions to go
over. Have your note sheets ready.
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Turn the packet in to the bin at the front.
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What pieces of information would
help you answer this question?
Write down any strategies you can use to answer the question.
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Objectives
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Articulate that this electromagnetic radiation is given off as photons.
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• Understand the inverse relationship between wavelength and
frequency, and the direct relationship between energy and frequency.
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• Use the “Bohr Model for Hydrogen Atom” and “Electromagnetic
Spectrum” diagrams from the Reference Tables to relate color,
frequency, and wavelength of the light emitted to the energy of the
photon.
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• Explain that Niles Bohr produced a model of the hydrogen atom based
on experimental observations. This model indicated that:
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1. an electron circles the nucleus only in fixed energy ranges called
orbits; 2. an electron can neither gain or lose energy inside this orbit,
but could move up or down to another orbit; 3. that the lowest energy
orbit is closest to the nucleus.
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• Describe the wave/particle duality of electrons.
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Homework
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Finish any homework or assignments that you need to finish
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Turn these in tomorrow morning!!!!!!!!!!!!!!!
Stay tuned for a wardrobe request
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On light, and color
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http://web.archive.org/lessons/how-do-we-see-color-colmkelleher#review
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Before reading…
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Group A: List everything you know about particles
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Group B: List everything you know about waves
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Group C: List everything you know about light
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Read and annotate the article
What evidence does the author present?
What are some things the author doesn’t consider?
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Next:
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Groups get together: collect and refine evidence for your
view of the electron
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Each group presents their view of the electron
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
http://phys.org/news/2015-03-particle.html
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Homework:
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Group A: wear green
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Group B: wear blue
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Group C: wear red
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This is for bonus points on your next quiz
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Catalyst 9/25
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Take out the worksheets related to “Electron Configuration”
that I gave last week.
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Turn in any overdue homework
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All this is done silently
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Start looking over all the questions. Start by checking off
which ones you feel you cannot answer. Circle those, and on
the index card, write what information you’ll need to solve
them.
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Then answer the ones you feel you know.
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Objectives/Plan for today
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Understand electron configuration as modeled by the Bohr
and Electron Cloud model
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Understand light
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Prepare for review for Tuesday Quiz
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Catalyst 9-28
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Write out the Orbital Notation and Electron Configuration for
Iodine
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Iodine-127 is the most stable and common isotope for the
element. What is the atomic mass of Iodine-127?
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How many protons are in Iodine 127? How many neutrons?
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Given that the Periodic Table shows Iodine with an atomic
mass of 126.90, what does this say about the natural
abundance of Iodine 127?
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Objectives
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Understand Bloom’s Revised Taxonomy
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Review material from this objective
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Create study guides for further review
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Prepare for quiz tomorrow
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Bloom’s Taxonomy applied
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Your study guide
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Must address all objectives
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Can be no more and no less than 12 questions
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One question should be an exploration of a certain element, as
demonstrated in the catalyst
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This element must be in the fourth period or below
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Should have a question that applies each of the bottom four
levels of Bloom’s Revised Taxonomy
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Bonus points for each additional objective covered in the same
question and each additional level of thinking (Bloom)
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Group with the most points gets a bonus point on the quiz