Ch. 13 Quantum Mechanical
Model
Electron Configuration
Quantum Mechanical Model
• Quantum mechanics was developed by Erwin
Schrodinger
• Estimates the probability of finding an e- in a
certain position
• Electrons are found in an “electron cloud” or
orbital
Orbital (“electron cloud”)
– Region in space where there is 90% probability of
finding an e-
Orbital
Radial Distribution Curve
Each orbital letter has a different shape.
“s” orbital
spherical shaped,
and holds up to
2e-
“p” orbital
Dumbbell shaped
Arranged x, y, z axes, and can
hold up to 6e-
“d” orbital
clover shaped, and can hold up
to 10e-
“f” orbital
• Orbitals combine to form
a spherical shape.
• This orbital can hold up to
14e-
f
2px
2py
2s
2pz
Hog Hilton
You are the manager of a prestigious new hotel in downtown
Midland—the “Hog Hilton”. It’s just the “snort of the town”
and you want to keep its reputation a cut above all the other
hotels. Your problem is your clientele. They are hogs in the
truest sense.
Your major task is to fill rooms in your hotel. The Hog Hilton only
has stairs. You must fill up your hotel keeping the following
rules in mind:
1) Hogs are lazy, they don’t want to walk up stairs!
2) Hogs want to room by themselves, but they would rather
room with another hog than walk up more stairs.
3) If hogs are in the same room they will face in opposite
directions.
4) They stink, so you can’t put more than two hogs in each
room.
Hog Hilton
• Your hotel looks like the diagram below:
6th floor ______
5th floor ______ ______ ______
4th floor ______
3rd floor ______ ______ ______
2nd floor ______
1st floor ______
Book 7 hogs into the rooms.
Hog Hilton
Your hotel looks like the diagram below:
6th floor ______
5th floor ______ ______ ______
4th floor ______
3rd floor ______ ______ ______
2nd floor ______
1st floor ______
Book 14 hogs into the rooms.
Let’s play Hog Hilton!!
Rules for
e configurations
1. Aufbau principle: e- enter orbitals of lowest energy
level (Hogs are lazy, they don’t want to walk up stairs!)
2. Pauli exclusion principle: an atomic orbital may
have at most 2 e-, e- in the same orbital will spin in
opposite directions (They stink, so you can’t put more than
two hogs in each room. & If hogs are in the same room they
will face in opposite directions.)
3. Hund’s rule: when e- occupy orbitals of = energy, 1
enters each orbital until all the orbitals contain 1 ew/parallel spins (Hogs want to room by themselves, but
they would rather room with another hog than walk up more
stairs.)
Now you will relate the “Hog Hilton” to electron orbitals. Electron orbitals are
modeled by the picture on the left and are grouped into principal energy levels.
1. Compare their similarities and differences.
2. To go between floors on the Hog Hilton did the hogs need to use energy? Would
electrons need to use the energy to go between orbitals.
3d ___ ___ ___ ___ ___ n=3
(4s ____) n=4
3p ___ ___ ___ n=3
3s ___ n=3
2p ___ ___ ___ n=2
2s ___ n=2
1s ___ n=1
6th floor ___
5th floor ___ ___ ___
4th floor ___
3rd floor ___ ___ ___
2nd floor ___
1st floor ___
Organization of e- in the
Quantum Mechanical model
A. The principle quantum numbers, (n)
•
Electrons are in designated energy levels.
The ground state- the lowest energy state of the atom
B. Within the energy level are sublevels, designated
by letters.
Principle energy
level (n)
1st energy level
Number of
sublevels
1 sublevel
Type of Orbital
“s” (1 orbital)
2nd
2 sublevels
“s” (1) & “p” (3 orbitals)
3rd
3 sublevels
“s”(1) , “p” (3) & “d” (5
orbitals)
4th
4 sublevels
“s”(1), “p”(3) , “d”(5), and “f”
(7)
7s
6s
6p
5d
4f
5p
4d
5s
4p
3d
4s
3p
3s
2p
2s
1s
7s
6s
5s
4s
3s
2s
1s
7p
6p
5p
4p
3p
2p
6d 6f 6g
5d 5f 5g
4d 4f
3d
Filling in orbitals then writing the electron
configuration
4p _ ↑↓ _
3d _ ↑↓ _
4s _ ↑↓ _
3p _ ↑↓ _
3s _ ↑↓ _
2p _ ↑↓ _
2s _ ↑↓ _
1s _↑↓_
_ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
D. According to their e- configs, elements can be
classified into 4 main groups
1. Noble Gases – outermost s & p sublevels filled
Because they have their s2 & p6
orbitals filled they follow the:
2 + 6 = OCTET RULE
2. Representative Elements – outermost s or p
sublevel is only partially filled, energy level same
as period #
s1
The pink elements excluding the Noble Gases.
s2
p1 p2
p3 p4 p5
3. Transition metals – outermost s sublevel &
nearby d sublevel contain e- , energy level is the
same as the period # minus 1
d1 d2 d3 d4 d5 d6 d7 d8 d9 d10
4. Inner Transition metals - outermost s & nearby f
generally contain e-
f1
f14
Your Periodic Table should look like this.
s1
s2
p1 p2
p3 p4 p5
s2
p6
d1 d2 d3 d4 d5 d6 d7 d8 d9 d10
f1
f14
Learning Check
How many electrons are present in the d sublevel of a
neutral atom of Manganese?
1 2 3 4 5
5 electrons
What element has the electron configuration
1s22s22p63s23p4?
Add together all the exponents, then find that
atomic number. = Sulfur 16
E. Using the Noble Gases to write Shorthand
• Write the noble gas that is in the previous row.
• Use the symbol of the noble gas, put it in
brackets, then write the rest of the configuration.
Write the e- config using Noble Gas notation for Cobalt.
It would be written [Ar] 4s2 3d7
• Write the e- config for Tin (Sn).
• [Kr] 5s2 4d10 5p2
Learning Check
Using the Noble Gas Shorthand write the e- configuration
1. Cr
[Ar] 4s2 3d4
2. Br
3. Te
4. Ba
[Ar] 4s2 3d10 4p5
[Kr] 5s2 4d10 5p4
[Xe] 6s2
Electromagnetic Spectrum
• The electromagnetic spectrum (see p. 373) includes radio
waves, microwaves, infrared waves, visible light,
ultraviolet waves, x-rays, and gamma rays.
• Visible light is in the middle of the spectrum.
• The speed of light is 3.0 X 108 m/s.
• The formula for light is c
=ƛʋ
• C = speed of light, ƛ = wavelength, ʋ = frequency
– Visible light has many wavelengths of light that can be
separated into red, orange, yellow, green, blue, indigo,
and violet (ROY G BIV)
Atomic Emission Spectrum
• Every element gives off light when it is excited by
the passage of an electric current through its gas
or vapor.
• The atomic emission spectrum occurs when the
light that is given off by an element in its excited
state is passed through a prism. It consists of a
few lines called a line spectra or discontinuous
spectra. Each line on the spectra corresponds
with a frequency.
• See page 374.
• Work problems # 11 and 12 on page 375.
Planck’s Constant
• In 1900, German Physicist Max Planck used math
to explain why objects, such as iron, that are
heated change color.
• He said energy can be quantized. The size of an
emitted or absorbed quantum depends on the
size of the energy change. A small energy change
involves the emission or absorption of low
frequency radiation. A large energy change
involves the emission or absorption of high
frequency radiation.
Planck’s constant cont.
• The math formula used is:
E=hxv
E = radiant energy of a unit (quantum)
h = Planck’s constant = 6.6262 x 10 -34
v = frequency of radiation
Planck’s constant cont.
• In 1905, Albert Einstein used Planck’s work to
call quanta of light photons. He then used this
information to explain the photoelectric effect
(metals eject/emit electrons called
photoelectrons when light shines on them).
• Work problems 13 and 14 on p. 379.