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Describe characteristics of a wave (wavelength, frequency, energy)
Explain how wave characteristics are related
Explain how light and different colors of light are produced
Define the electromagnetic spectrum
Explain Bohr models including their advantages and disadvantages
Determine the electron configuration and/or orbital diagram of any atom or ion;
use these to determine groups, periods and identities of elements along with
things such as number of unpaired electrons
Define the periodic trends and be able to compare to elements and explain their
difference with regards to these trends
Describe the role of probability in orbital theory
Determine if an ion for a given element will be a cation or anion and explain how
each type of ion is formed
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Ground state
Excited state
Wavelength
Frequency
Energy
Photon
Electromagnetic spectrum
Energy level
Orbital
Valence electron
electron configuration
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Core electron
Alkali metal
Alkaline earth metal
Halogen
Actinide
Lanthanide
Atomic radius
Ionization energy
Electronegativity
Transition element
Main-group element
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For a chemical reaction to occur, the atoms and/or molecules
involved must physically collide with each other
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If two atoms react, which part of the atoms will interact with each
other first?
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The structure and arrangement of _________________________
therefore, is the key to understanding chemical reactivity
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The arrangement of electrons was determined by studying how
atoms absorb and emit electromagnetic radiation, e.g. light
EM radiation is one way that energy travels through space
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EM radiation has 3 characteristics: speed, wavelength, and
frequency
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The speed of light (c), is a
constant for all forms of
EM radiation in a vacuum
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We will always assume
that EM radiation is moving
through a vacuum
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c = 3.0 x 108 m/s
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The 2nd characteristic of waves is wavelength (λ)
Wavelength is the distance between two peaks
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Frequency (ν) indicates how many peaks pass a given point each
second and is the 3rd characteristic
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Frequency (ν) indicates how many peaks pass a given point each
second and is the 3rd characteristic
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The characteristics are related by the following equation:
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Be careful with units! Make sure everybody matches up!
Given that c is a constant, what kind of relationship does this show
between wavelength and frequency?
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The energy of the radiation is also related to the frequency of the
radiation
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The fun part is that light behave like a wave, but it also shows
behaviors characteristic of particles, in this case called photons
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The equation below gives the energy of EM radiation, and is equal
to the energy of one single photon; QUANTIZED!
A.
B.
C.
D.
1.95 x 1011
4.61 x 105
1.95 x 102
4.62 x 1014
A.
B.
C.
D.
4.42 x 10-19
4.42 x 10-28
8.95 x 10-32
1.01 x 1048
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Atoms are normally found in their ground state, which is the lowest
energy state of an atom
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When an atom absorbs
energy, for example from
electricity, the atom enters
the excited state
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When the atom is excited, the
electrons move to higher
levels
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Excess energy makes the atom unstable, and the excess energy is
released as a photon (light) to return the atom to the ground state
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White light contains every wavelength of visible light, and products
a continuous spectrum
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Other times, only certain wavelengths are emitted producing a line
spectrum
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Substances emit different wavelengths because they absorb and
emit different amounts of energy due to differing numbers and
arrangements of electrons
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Each substance has its own
unique line spectrum
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These can be used to identify
unknown substances
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Niels Bohr used the idea that electrons can only possess certain
amounts of energy to develop the Bohr model; this model showed
electrons traveling in fixed, circular orbits
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Sadly, Bohr was wrong…atoms
with more than one electron blow
this idea to tiny little pieces
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But atoms and electrons being
quantized was pretty frickin’
smart of him
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A key development in understanding the structure of the atom was
Schrodinger’s wave equation, which lead to quantum
mechanics...Heisenberg helped a little, too...
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Solving this equation leads to a series of wave functions, which is
essentially a set of x, y, and z coordinates
Each point graphed as a result of these coordinates indicates the
possible location of an electron
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Graphing a lot of these points gives a map of the probable location
of an electron; the exact location of an electron is pretty much
impossible to determine
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Each point gives a possible
electron location; more dots
means a higher probability
of an electron being there
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The area of space in which an
electron is most likely to be
found is called an orbital
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This is done for every electron they can get their hands on, for
example p-orbitals
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Notice that there are three ways the p-orbital can be oriented in
space…this means there can be three p-orbitals!! Sweet!
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And d-orbitals…
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And f-orbitals…just to blow your mind!
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Each orbital (or area of space) can hold a maximum of 2 electrons.
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One or more orbitals combine to make sublevels or subshells
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The sublevels consist of different shapes of orbitals, and are
designated using letters
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The four different shapes of orbitals are s, p, d, and f
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So an f-sublevel consists of f-orbitals, a d-sublevel consists of dorbitals and so on…
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Something to help clarify this is to think of an atom as a hotel
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If the atom is a hotel, each energy level is a floor of the hotel
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The sublevels are different types of rooms on that floor
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The orbitals are the individual rooms
on each floor
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Each room (orbital) has a maximum
occupancy of 2 people (electrons)
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Electron configurations and orbital diagrams are used to show the
location (probable) of electrons in an atom
Electron configurations use the notation seen below:
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Orbital notation looks like this fun stuff down here:
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Electron configurations and orbital notations are determined by
applying the relationship between the periodic table and the
structure of atoms (which you figured out in your lab)
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Let’s find the e- configuration and orbital notation for oxygen...and
while we’re at it, say hello to Pauli and Hund!
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Now how about iron?
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And what about bromine?
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And lets try neodymium (atomic #60) ?
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And for fun, lead!
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What is incorrect about orbital notation below?
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What is incorrect about orbital notation below?
A.
B.
C.
D.
Vanadium
Argon
Iron
Cobalt
A.
B.
C.
D.
Chlorine
Fluorine
Oxygen
Neon
A.
B.
C.
D.
Vanadium
Phosphorous
Oxygen
Sulfur
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Noble gas notation gives a way of shortening the electron
configuration and focusing on valence electrons
Element
Electron Configuration
Noble Gas Config.
Sodium
1s2s2p63s1
[Ne] 3s1
Argon
1s22s22p63s23p6
[Ne] 3s23p6
Silicon
1s22s22p63s23p2
[Ne]3s23p2
Fluorine
1s22s22p5
[He] 2s22p5
Beryllium
1s22s2
[He] 2s2
Iron
1s22s22p63s23p64s23d6
[Ar] 4s23d6
Lead
1s22s22p63s23p64s23d104p65s24d105p66s25d104f146p2
[Xe] 6s25d104f146p2
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Based on the noble gas configurations on the previous slide, write
steps to use in determining the noble gas configuration of an
element.
[Kr] 5s24d8
A.
B.
C.
D.
Ni
Pd
Pt
Ag
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The electron configurations of ions are determined by keeping
track of the number of electrons gained/lost and exactly where
they are added to or removed from
Metals lose electrons forming positively charged ions called
cations
Metals lose electrons from the highest energy level
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Nonmetals gain electrons forming negatively charged ions called
anions
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Nonmetals gain electrons in the highest energy SUBlevel
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Write the electron configuration and noble gas configuration for the
nitride ion, N3-.
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Write the electron configuration and noble gas configuration for the
Cadmium ion, Cd+2.
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The structure of the atom, as reflected in the periodic table, can be
used to determine and predict various properties of atoms
Ionization energy: the energy required to remove an electron from
a gaseous atom or ion
Atomic Radius: Half the distance between the nuclei of two atoms
Electronegativity: the ability of an atom in a molecule to attract
shared electrons
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With each property, it is all about how strongly the nucleus of the
atom attracts valence electrons; two factors impact this
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Coulomb’s Law illustrates these two factors:
F = electrostatic force
r = distance between charge centers
q = electric charge
k = who cares?
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So think about this in terms of an atom:
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The charge factor is about more than just the number of protons in
the nucleus
The focus is on the nucleus attracting the valence electrons, so the
core/inner shell/shielding electrons must be considered
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The core electrons cause the shielding effect
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Core electron cause a decrease in the amount of attractive pull felt
by the valence electron(s)
More core electrons = larger decrease
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This is summed up by the effective nuclear charge(Zeff)
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Find the Zeff for the following elements; then describe how the Zeff
changes moving from top to bottom within a group
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Find the Zeff for the first four elements below; then describe how
the Zeff changes moving from left to right within a period
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Distance between the nucleus and the valence electrons is all
about the number of energy levels
More energy levels means valence electrons farther from nucleus
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Distance between the nucleus and the valence electrons is all
about the number of energy levels
More energy levels means valence electrons farther from nucleus
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So when comparing two elements in a period, which factor
causes them to have different properties? Which is ignored?
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And when comparing two elements in the same group, which
factor causes them to have different properties? Which is
ignored?
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Ionization energy is the energy needed to remove a valence electron
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Does a high ionization energy mean an atom has a strong attraction
for its valence electron(s) or a weak attraction?
Ionization Energies
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Which has a higher ionization energy: lithium or fluorine? Explain.
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Which has higher ionization energy: lithium or potassium? Explain.
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Electronegativity is the ability of an atom to attract shared electrons
when bonded to another atom
Electronegativity Values
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Which has a greater electronegativity: lithium or fluorine? Explain.
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Which has a greater electronegativity: lithium or potassium? Explain.
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Atomic radius is defined as half the distance between the nuclei in a
molecule consisting of identical atoms
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More simply, the atomic radius can be thought of as the size of an
atom
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Since the boundary of an atom can’t be defined, we can’t just
measure from one side of an atom to another
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Which atom is larger: lithium or fluorine? Explain.
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Which atom is larger: lithium or potassium? Explain.
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Changes that occur with ions can be determined similarly; draw a
Bohr model for a neutral lithium atom and an lithium ion below.
Describe how their radii differ and why this difference exists.
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Now do the same for a Bohr model for a neutral fluorine atom and a
fluoride ion below. Describe how their radii differ and why this
difference exists. They are not the same size!!!
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And now draw a fluoride ion, and oxide ion, and a sodium ion.
Arrange them from smallest to largest, and explain the order selected.
A.
B.
C.
D.
E.
Ni, Br, Ca
Br, Ca, Ni
Ca, Br, Ni
Ca, Ni, Br
Br, Ni, Ca
A.
B.
C.
D.
E.
I, Br, F
Br, I, F
F, Br, I
I, F, Br
Br, F, I
A.
B.
C.
D.
E.
N, Rb, Ca
Ca, Rb, N
Rb, N, Ca
N, Ca, Rb
Rb, Ca, N