Transcript Ch. 13 Notes---Electrons in Atoms

Ch. 11 Notes---Modern Atomic Theory
Atomic Models
Thomson
(1)
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a ball of (+) charge containing a number of enucleus
no ________________
plum _______________”
pudding
often described as the “________
atom.
Rutherford
(2)
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•
Model:
Model:
nucleus
a ____________
of (+) charge surrounded by
a number of eneutrons
no _____________
and no e- orbitals
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Atomic Models
Bohr
(3)
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Model:
neutrons
a nucleus of (+) charge that also contains ______________
nucleus is encircled by e-’s located in definite orbits (or
paths).
fixed
e-’s have ___________
energies in these orbits
e-’s do not lose energy as they orbit the nucleus
Quantum Mechanical Model ( Wave Mechanical Model)
(4)
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shape
no definite ____________
to the e- path (“fuzzy” cloud)
probability
orbits of e-’s based on the _________________
of finding the
e- in the particular orbital shape.
Bohr Atomic Model
Bohr Atomic Model
Quantum Mechanical Model
Quantum Mechanical Model
Quantum
Mechanical
Model
Energy Levels
Diagram: (Fig. 11.10)
• The energy levels in an atom are
rungs of a ladder.
sort of like _________
• The more energy an electron has,
farther away from the
the __________
nucleus it usually will be.
“excited
state”
• The energy levels are not evenly
closer
spaced. They get ___________
together as you travel farther away.
• To move from one “rung” to
quantum
another requires a “____________”
of energy.
“ground
state”
Figure 11.15: The difference between continuous and quantized energy levels.
continuous energy levels
quantized energy levels
Quantum Numbers
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location
Describe the ______________
of the e-’s around the nucleus.
•
This information about the location of the e-’s in an atom can be
used to:
address
Quantum #’s are sort of like a home _____________
for the
electron.
properties
(1) determine chemical & physical _____________
for the
elements.
Periodic
Table
(2) show how the _______________
__________
is organized.
how and _____
why elements combine to form
(3) show _____
compounds.
The Four Quantum Numbers
1.
Principal Q. #: Describes the _____________
distance
that the
electron is from the nucleus. The bigger the number, the
farther away the electron is.
___________
Example: (1=closest, 2, 3, 4...farther away)
principal
These distances are sometimes called _______________
energy
levels
______________
____________.
1
2
3
nucleus
shape
2. Orbital Q. #: Describes the __________
of the electron’s path
around the nucleus with a letter: (s, p, d, & f) These are
sublevels
sometimes called “_____________”.
spherical cloud;
s=_____________
ellipsoid
p=_____________
or a 3-D figure 8;
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d & f orbital shapes are
criss
complex ________crossing
_______________
ellipsoids, and some d’s
and f’s are an ellipsoid
with a doughnut or two
around the middle.
All of these orbital shapes
are based on the probability
of finding the electron in
the cloud.
f - orbitals
d - orbitals
Figure 11.22: How principal energy levels can be divided into sublevels.
s
p
d
s
p
f
d
s
p
s
A Way to Visualize s, p, d, and f sublevels
1 sublevel
2 sublevels
3 sublevels
•
Magnetic Q. #: tells how many _________________
orientations
in 3-D there
are about the nucleus for each orbital shape.
s=___
1 orientation
5 orientations
d= ___
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3 orientations... (x, y, and z)
p= ___
7 orientations
f= ___
The orientations are represented with a line or a box.
Examples: ___
1s
spherical orbital at a distance of
This means a __________
1 (close) to the nucleus. This orbital is
“__”
centered about the x, y, and z axis.
□□□
with its
of “___”
4p 3
This representsellipsoid
an ___________ orbital
4
____ possible orientations at a distance
from the nucleus.
Figure 11.23: Principal energy level 2 shown divided
into the 2s and 2p sublevels
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Spin Q. #: describes how the electron in an orientation is spinning
up or
around the nucleus. This spin can be thought of as “____”
down
“________”.
(Some like to imagine it spinning “clockwise” and
arrow
“counterclockwise”.) The spin is represented as an ___________
in the direction of the spin.
Example: ↑
2s
“___”
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spherical
This represents one electron in a _________
up at a distance of 2
orbital with spin “____”
from the nucleus.
Remember, the four quantum numbers tell us the location, or
“address” of each electron in an atom.
This information is vital in understanding the layout of the Periodic
Table and the reasoning behind why and how atoms form bonds.
Electron Configurations
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Electron configurations are notations that represent the four
Quantum #’s for all of the electrons in a particular atom. Here are
the rules for these notations:
Rule #1 (Aufbau Principle): Electrons fill ________
lowest energy
orbitals first.
Examples: 1s would be filled before ____
2s
3s would fill before ____
3p
Electron Configurations
Silicon
↑ ↑
↑↓
↑↓ ↑↓ ↑↓
↑↓
(Energy Level Diagram)
↑↓
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
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Rule #2: Only ___
2 electrons can fit into each orientation.
↑↓
Example: ___
1s
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↑↓↑
not ____
1s
Rule #3 (Pauli Exclusion Principle): Electrons in the same
orientation have ______________
spin.
opposite
Example:
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↑
___
2s
↑ ↓ not ___
↑↑
___
1s
1s
Monopoly
Rule #4 (Hund’s Rule): “_______________
rule”---> Every
□
“
” in an orbital shape gets an electron before any orientation
gets a second e-.
Example:
□□□
↑
↑
2p
↑
↑↓
not↑
2p
□□□
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Rule #5: The Exceptions
–
lower
Half-filled or completely filled d & f sublevels have ________
energies and are more stable than partially filled d’s and f’s.
–
This means that an atom can “borrow” one of its “s” electrons
from the previous orbital to become more stable.
Example:
↑↓
___
5s
becomes
–
↑ ↓ ___
↑↓
↑↓
↑↓
↑
___
___
___
___
4d
↑↓
___
↑
↑↓
↑↓
↑↓
↑↓
___
___
___
___
___
5s
4d
lower
Because the 4d sublevel is now full, the atom is at a ________
more stable.
energy state and therefore _________
Electron Configurations
Practice Problems:
Write the electron configuration notation for each of the following
atoms:
• Hydrogen
• Carbon
• Iron
• Bromine
Shorthand Method: Assumes we already know about the # of
• H
• C
• Fe
• Br
□.
How Electron Configurations Relate to the
Organization of the Periodic Table
s
p
d
f
Figure 11.31: Orbitals being filled for elements in various parts of the periodic table.
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Electron Configurations & Properties
How do electron configurations relate to the chemical and physical
properties of an element?
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same outer shell e- configurations have
All elements with the _________
________
similar properties.
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vertical
This means that elements in the same ____________
group have
similar properties.
1 lone “__”
s e- for
Examples: (1) Li, Na, K, Rb, and Cs all have __
their last orbital... (_____,
2s1 _____,
3s1 _____,
4s1 etc.) This makes all of
very
water to
them ___________
reactive. They all react with __________
produce hydrogen gas.
(2) Ne, Ar, Kr, Xe, and Rn all have the outer energy level
filled
2s2 2p6
3s2 3p6
completely __________
with electrons...(________,
________,
4s2 4p6 etc.) This makes all of them ______________.
inert
________,
They do not produce __________________!
compounds
More Practice Problems
Bromine
(1) Which element has its last electron as a 4p5? ___________
F, Cl, I, At
(2) Which elements are similar in properties as Bromine? __________
(3) What would the outer shell electron configuration look like for the
element underneath Radon, (Rn)?
…7s2 5f14 6d10 7p6
4f1
(4) Which electron is added after 6s2? ________
(5) Which element would “borrow” a 5s electron to get a half-filled
Mo
“d” sublevel? ___________
sphere
(6) What is the shape of the last orbital filled in Calcium, (Ca)? _____
4
(7) How many electrons are in the last “p-orbital” of Sulfur, (S)? ____
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Electromagnetic Radiation
Any wave of energy traveling at a speed of ___________
light
is called
electromagnetic radiation.
There are many types of electromagnetic radiation and each type has
a different _______________
and _______________.
frequency
wavelength
Here are the types of electromagnetic radiation from longest to
shortest wave or lowest to highest frequency. These are also in order
from lowest to highest energy.
Electromagnetic Radiation
Electromagnetic Radiation
(1) Radio Waves -- used in __________________
communications
cook _______.
food
(2) Microwaves-- broadcasts TV signals and used to _____
heat _________
Snakes & ______
owls can
(3) Infrared (IR) -- we feel this as _____;
“see” this.
infrared image of a cat
infrared image of heating pipes under a floor
Infrared
Vision
Electromagnetic Radiation
(4) Visible Light -- the only radiation we can detect with our eyes. It
prism
can be separated into the colors of the spectrum with a __________.
ROYGBIV
sunburn
Bees can
(5) Ultraviolet (UV) -- gives you a _____________;
_________
“see” this; some of this radiation from the sun gets blocked by the
ozone layer
___________
flower photo under normal light
flower photo under UV light
Electromagnetic Radiation
(6) X-rays -- used in medicine
Ouch!
Electromagnetic Radiation
(7) Gamma Rays-- some radioactive substances give it off
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Cosmic
_______________Rays
– These are not part of the EM spectrum…
They are high energy particles (mostly protons); They cause the
northern lights.
Interesting superhero facts:
• Superman has x-ray vision.
• The Incredible Hulk was
“created” by an accidental
overdose of gamma radiation.
• The Fantastic Four were
“created” by cosmic rays.
How Light is Produced
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When atoms get hit with
zapping
energy (by _____________
them with electricity or by
heating
____________
them up), the
electrons absorb this energy
and __________
jump
to a higher
energy level. Figure (a)
As they immediately fall back
down to the “____________
ground
state”, they give off this
energy in the form of a
light
particle of ___________
(or
other types of electromagnetic
radiation) called a
photon
_____________.
Figure (b)
How Light is Produced
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Each photon emitted has a
color
specific ___________
(or
frequency).
The color of the light that is
given off depends on how
far the electron _______
fell
_____
(which depends on how big
of a jump it originally made.)
The farther the fall, the
greater
___________
energy the
photon has.
Figure 11.6: Photons of red and blue light.
How Light is Produced
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energy levels (or
Since electrons are located only in certain __________
orbitals) around the nucleus, only certain specific _________
color of light
are emitted.
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spectroscope
Scientists use a _________________
to separate these colors into
bar code of color
bands of light. These bands of color look like a ______
which is characteristic of that element. No two elements produce the
spectrum
same ______________
of colors. This can be used to distinguish one
element from another contained in a sample. (See Fig. 13.11)
Emission Spectrum
Hydrogen
Spectrum
Neon
Spectrum
How hydrogen
produces the four
visible photons
All the Photons Produced by Hydrogen