Ch. 7 – Atomic Structure and Periodicity
 In this chapter we will see that the modern theory of atomic structure…
 Quantum mechanics was developed to account for …
7.1 Electromagnetic Radiation
Electromagnetic radiation
Ex’s
Wavelength ( )
Frequency ( )
Eqn:
<<Draw pictures that depict the meaning of wavelength
and frequency and how they relate. E.g. Fig 7.1>>
Sample exercise 7.1 – Frequency of Electromagnetic Radiation (complete below)
7.2 Nature of Matter
 At the end of the 19th century the idea prevailed that …
MATTER
1)
2)
3)
ENERGY
1)
2)
3)
1
Max Plank
 Studied…
 Found …
 Postulated…
ΔE =
Where n =
h=
 Had assumed energy of matter was __________________.
 Energy is in fact ______________.
which means…
KEY: This means energy has __________________ properties.
Sample Exercise 7.2 – The energy of a photon (complete below)
Albert Einstein
 Proposed…
 Suggested that electromagnetic radiation can be viewed as…
 Ephoton =
Photoelectric effect Observations:
1. Studies in which the frequency of the light is varied show that no electrons are
emitted by a given metal below a specific threshold frequency, o
2. For light with frequency lower than the threshold frequency, no electrons are
emitted regardless of the intensity of the light.
3. For light with frequency greater than the threshold frequency, the number of
electrons emitted increases with the intensity of the light.
4. For light with frequency greater than the threshold frequency, the kinetic energy,
of the emitted electrons increases linearly with the frequency of the light.
KEY: These observations can be explained by assuming…
(and that the threshold frequency represents the minimum energy
required to remove the electrons from the metal’s surface.)
Light intensity is a measure of ______________
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Related development, famous eqn:
E=
Main significance: ________________________________
Thus we can calculate the mass of a ___________.
Note: This is only in a ___________ sense; there is no ______ mass.
Summary of Plank and Einstein
1.
2.
De Broglie Eqn:
=
Key: it allows us to calculate the ________________________
Sample Exercise 7.3 – Calculations of Wavelength (complete below)
(Take note of the relative ’s you just calculated. How do they compare in size?)
Diffraction –
Ex’s
____________ directed at a NaCl crystal produce ______________.
KEY: diffraction patters can only be explained ___________________________.
Thus diffraction provides a test for deBroglie’s postulate that ____________________
 Diffraction patterns occur most efficiently when …
 When a beam of __________ were directed at a Ni crystal, Davisson and
Germer observed _________________________ which verified
_______________________________________________.
KEY: This means electrons ________________________.
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SUMMARY:
 Electromagnetic Radiation ________________________________.
 Electrons _______________________.
All matter exhibits…
7.3 The Atomic Spectrum of Hydrogen
Fig 7.6
Impt. Expt. – study of the ________________
___________________________
 Hydrogen atoms release excess energy
by __________________________ to
produce _______________________.
Significance:
…in other words:
ΔE =
7.4 The Bohr Model
 Bohr developed the first ________________
for the hydrogen atom.
 He proposed…
 He calculated…
o With the assumption that angular momentum…
Bohr’s model gave the hydrogen atom energy levels consistent with _________________.
Fig. 7.8
4
Important equation is the expression for the energy levels available to the electron
in the hydrogen atom:
E=
n=
Z=
Negative sign means…
 Bohr calculated hydrogen atom energy levels that …
Calculate the energy of a hydrogen atom when its electron is…
at n = 6
at n = 1
Calculate ΔE when the electron falls from n = 6 to n = 1.
Calculate the wavelength of this emitted photon.
Sample Exercise 7.4 – Energy Quantization in Hydrogen
Two Points of emphasis for Bohr’s model:
1.
2.
In the space below, derive the general equation for determining the energy change when an
electron moves from one level to another. (pg. 287)
Sample Exercise 7.5 – Electron Energies
NOTE: Bohr’s model applied to other atoms ___________________.
KEY: Bohr’s model paved the way for later theories.
Electrons do NOT _____________________________.
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Balmer, Lyman, and Paschen Series:
7.5 The Quantum Mechanical Model of the Atom
Werner Heisenberg –
Louis deBroglie originated the idea that…
Erwin Schrodinger gave emphasis to…
Electron bound to the nucleus is similar to __________________________.
KEY: there are limitations on ____________________________________.
 Considering the wavelike properties of the electron is a possible explanation
for the observed _____________________________________.
Schrodinger’s eqn:
 When the equation is analyzed _________ solutions are found.
 Each solution consists of a ______________ that is characterized by a
___________________________ (for an electron).
 A specific wave function is often called an _________________.
 An orbital is NOT __________________.
 The wave function gives us _____ information about the ______________
______________________________________.
Heisenberg Uncertainty Principle –
Eqn:
What this equation really says is…
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The physical meaning of a wave function
 Psi itself has ___ easily visualized meaning.
 psi2 indicates __________________________________________.
Eqn:
psi2 is conveniently represented as a __________________________.
Fig. 7.11
This is of a hydrogen 1s wavefunction
 The total probability of finding the electron at a particular distance is called
________________________________.
Fig. 7.12
 The maximum in the curve occurs because of the _____________________.
1.
2.
 Orbitals usually described as the radius of the sphere that encloses _____%
of the total electron probability.
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7.6 Quantum Numbers
1st number:
2nd number:
3rd number:
Sample Exercise 7.6 – Electron subshells (complete below)
7.7 Orbital Shapes and Energies
Fig. 7-13
Methods of representing an orbital
1.
2.
nodes/nodal surfaces –
Orbital
s
p
d
f
# nodes
p-orbitals (fig. 7.14)
2px
2py
2pz
 Surfaces of orbitals _________________ as the value of n increases.
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Degenerate –
Ex. All 3d orbitals are degenerate
Fig. 7.18
E
4th Quantum Number:
Pauli Exclusion Principle –
Which means an orbital can only….
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7.9 Polyelectronic Atoms
Three energy contributions are important:
1.
2.
3.
Electron correlation problem –
 We treat electrons as if it were moving in a _____________________________
that is the net results of ______________________________ and the
____________________________ of all the ____________________.
 Each electron is _______________________ from nuclear charge by the
_________________________________.
Hydrogen-like orbitals
 Have the same ___________________
 Have different _____________________________ due to the
interplay between ____________________________ and
___________________________.
Hydrogen:
Polyelectronic atoms:
Ens
Enp
End
Enf
Ens
Enp
End
Enf
 The hump of electron density that occurs in the
_______________ very near the nucleus means that
although an electron in the 2s orbital spends most of its
time a little farther from the nucleus than does an
electron in the 2p orbital, it spends a small but very
significant amount of time very near the nucleus.
o We say the 2s electron ________________ the
nucleus more than the ______________ in the
___________________.
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 This penetration effect causes and electron in the 2s orbital to be
______________________________________________________ than an
electron in the 2p orbital.
 The 2s orbital is _________________________ than the 2p orbitals for a
polyelectronic atom
In general, the more effectively an orbital allows its ____________________
______________________________ the shielding electrons to be
______________________________________, the _____________ is the energy
of that orbital.
Fig. 7.22
7.10 The History of the Periodic Table
Johann Dobereiner –
John Newlands –
Julius Lothar Meyer
Dmitri Ivanovich Mendeleev
o Given most credit because…
o Predicted the existence of …
o Corrected several…
o The only fundamental difference between our current periodic table
and Mendeleev’s is…
7.11 The Aufbau Principle and the Periodic Table
Aufbau Principle –
Hund’s Rule –
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Valence electrons –
Core electrons –
Key: the elements in the same group (vertical columns) have the same
____________________________.
Unexpected electron configurations:
Chromium
Copper
Electron filling rules:
1.
Which can be explained by…
2.
3.
4.
5.
Note that sometimes and electron occupies a 5d orbital instead of a 4f
orbital because…
Note that sometimes and electron occupies a 5d orbital instead of a 4f
orbital because…
The group labels for Groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, and 8A
indicate…
The groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, and 8A are called
7.12 - Periodic Trends in Atomic Properties
Ionization Energy –
I1
I2
I3
I4
(use <, >, or = signs between each)
Because….
First Ionization energies
_______ as we go across a period because…
_______ as we go down a group because…
Discontinuities:
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Sample Exercise 7.8 The first IE for phosphorus is 1060 kJ/mol, and that for sulfur
is 1005 kJ/mol. Why?
Sample Exercise 7.9 Which atom has the largest 1st IE, and which one has the
smallest second IE? Explain your choices.
Electron Affinity –
Note: Many books define it as the energy ___________.
The more negative the energy, the _________________________________.
______________________________ across periods because…
N- vs. C- vs. OO2______________________________ down columns because…
Table 7.7 Electron Affinities
Of the Halogens
Atom
Electron
Affinity
(kJ/mol)
Fluorine has a smaller electron
affinity because…
F
Cl
Br
I
Atomic Radius –
Covalent radii –
Metallic radii –
_____________ across periods because…
_____________ down columns because…
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Sample Exercise 7.10 – Trends in Radii – Predict the trends in radius for the following ions:
Be2+, Mg2+, Ca2+, Sr2+.
7.13 – The Properties of a Group: The Alkali Metals
Information Contained in the Periodic Table:
1-3 Should be common knowledge by now. Write these down if desired. Pay
close attention to 4. It’s filled with facts you need to know well.
1.
2.
3.
4.
Alkali Metals
Down columns
Densities
____________
pp/bp
____________
First IE’s
____________
Atomic radii
____________
Ionic radii
____________
Ionic radii are ___________ than covalent radii
- Most characteristic chemical property of metals is ….
- Metal + nonmetal 
o Nonmetal acts as __________________
o Metal acts as ____________
2 Na(s) + S(s) 
6 Li(s) + N2 (g) 
2 Na(s) + O2(g) 
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Expected trend in reducing ability:
With water..
2 M(s) + 2 H2O(l) 
The order of reducing ability is:
Hydration Energies for Li+, Na+, and K+ Ions.
Ion
Hydration
Energy
(kJ/mol)
Li+
Na+
K+
Hydration energy –
Li atoms become Li+ ions more easily in _______________ than in ___________.
Potassium appears to react more violently with water because…
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