Transcript Chapter 4 FILL IN NOTESx

Chapter 4
Electrons
In Atoms
Properties of Light
 Electromagnetic

Radiation:
Electromagnetic Spectrum:
Properties of Light
Characteristics of Waves
 There

are 4 main characteristics of
waves:
1) Amplitude:
Characteristics of Waves
3
4
Characteristics of Waves
 2)
Wavelength:
Wavelength
=λ
Characteristics of Waves
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4
Characteristics of Waves
 3)
Frequency: the number of waves
that pass a given point in a specific
time. Measured in cycles per second
(cycle/second, or s-1) The SI unit for
this is Hertz. 1.0 Hz = 1.0 s-1
Frequency is designated by the Greek
symbol nu. Frequency = υ
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Characteristics of Waves
Characteristics of Waves
 4)
Speed: the speed of light is
constant. It is rounded to
8
3.00 x 10 m/s. The speed of
light is represented by the
letter c.
c = λυ
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The Photoelectric Effect
 Refers to the emission of electrons from a
metal when light shines on the metal.
 Quantum:
Max Planck, a German physicist studied
quanta of light and found:
The Photoelectric Effect
E = hυ
Where h is Plank’s
Constant and has a value
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of 6.6262 x 10 Js
(energy)
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The Photoelectric Effect
Einstein expanded upon this to propose that
light has a dual nature, acting as a wave
under some circumstances and a particle
under others.
Photon:
Line Emission Spectrum
Ground State:
Excited State:
Line Emission Spectrum
Emission Line Spectrum: a graph that
indicates the degree to which a
substance emits radiant energy with
respect to wavelength.
Continuous Spectrum: the emission of
a continuous range of frequencies of
electromagnetic radiation.
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H Emission Spectrum
Niels Bohr: a Danish physicist who
proposed a hydrogen-atom model
that linked the atom’s electron to
photon emission. (electrons circle the
nucleus in “orbits”)
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H Emission Spectrum
Emission Line Spectrum: a graph that
indicates the degree to which a
substance emits radiant energy with
respect to wavelenth.
Continuous Spectrum: the emission of
a continuous range of frequencies of
electromagnetic radiation.
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H Emission Spectrum
Emission Line Spectrum: a graph that
indicates the degree to which a
substance emits radiant energy with
respect to wavelenth.
Continuous Spectrum: the emission of
a continuous range of frequencies of
electromagnetic radiation.
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The Quantum Model
Heisenberg’s Uncertainty Principle:
Quantum Theory:
The Quantum Model
Quantum Numbers:
Quantum numbers were developed based
on the Shrödenger Wave Equation,
developed by Austrian physicist Erwin
Shrödenger.
The Quantum Model
Principal Quantum Number (n): indicates
the main energy level occupied by the
electron. Values are positive integers only
(1, 2, 3, 4… with 1 being the lowest energy
level closest to the nucleus)
Angular Momentum Quantum Number (l):
indicates the shape of the orbital. Values
are 0, 1…n-1)
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The Quantum Model
l=0=s
l=1=p
l=2=d
l=3=f
The Quantum Model
Magnetic Quantum Number (m): indicates
the orientation of an orbital around the
nucleus. Values, including zero, are –l to
+l
l = 0 = s orbital has only one orientation (sphere)
l = 1 = p has three orientations
l = 2 = d has five orientations
l = 3 = f has seven orientations
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The Quantum Model
The Quantum Model
The Quantum Model
The Quantum Model
Spin Quantum Number: indicates the two fundamental
spin states of an electron in an orbital. Values are +1/2 or
-1/2.
Electron Configurations:
Orbital Filling Diagrams
There are 3 basic rules, named after the scientists that discovered
them, that govern the filling of these orbitals with electrons…
1)
The Aufbau Principle:
Orbital Filling Diagrams
2) The Pauli Exclusion Principle:
3) Hund’s Rule: Electrons occupy equal
energy orbitals so that a maximum number
of unpaired electrons results, and all e- in
singly occupied orbitals must have the same
spin.
Orbital Filling Diagrams
- Each electron is designated as an arrow ()
- They can be Spin up ( ) or Spin down () - Each orbital is designated with a labeled
line: _____ or __ __ __
1s
2p
-Multiple lines show multiple orbitals (1 for
s, 3 for p, 5 for d)
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Orbital Filling Diagrams
Orbitals fill going straight across each
period (row) on the periodic table, from
the lowest energy level up. (Aufbau).
Don’t forget, when they pair, they have
opposite spins (Pauli), but they won’t
pair until each available orbital has an
unpaired electron in it first (Hund)
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Orbital Filling Diagrams
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Orbital Filling Diagrams
-
-
-
The orbitals can hold a certain number of
electrons:
s=2
p=6
d=10
f=14
Orbital Filling Diagrams
Hydrogen, with one electron, would have an orbital filling diagram
of:

1s
Helium, with 2 electrons, would be:

1s
Now you’re at the end of the first period, start again in the 2nd
period with 2s…
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Orbital Filling Diagrams
Lithium:
 
1s 2s
Be:
 
1s 2s
B:
 
 _ _
1s 2s
2p
Orbital Filling Diagrams
Which of these would be correct for oxygen (with 8 e-):

1s

1s
O:

  ?
2s
2p
OR

  
2s
2p
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Practice
Write the orbital filling notation for the
following elements:
1) Na:_________________________
2) F:__________________________
3) Ar:_________________________
4) Cu:_________________________
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Electron Configurations
Now your ready to write electron configurations. These are simply the
orbital diagrams written out with superscripts:
Lithium:
 
1s 2s would be written out as 1s2 2s1
Be:
 
1s 2s would be written out as 1s2 2s2
B:
 
 _ _
1s 2s
2p
would be written out as 1s22s22p1
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Practice
Write the electron configuration for the
following elements:
5) Mg:________________________
6) N:_________________________
7) Cr:________________________
8) Cl:________________________
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Electron Configurations
Noble-Gas Configuration: refers to an outer main
energy level occupied by eight e

Once a subshell is complete at the end of a
period, you can write subsequent
configurations as having the core of the
previous noble gas with the additional valence
electrons.
Sodium Na would have a noble gas notation
of:
Na3s1
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Practice
Write the noble gas notation for the following elements:
9) Ne:_________________________
10) Sb:_________________________
11) Y:__________________________
12) F:__________________________
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Ch. 4
The
End
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