Block 26: Th 11/7 or F 11/8
• Sapling #11 due T 11/12
• Flame test lab due next class
• Debrief flame test
Quantum Mechanical Model,
Electron Configuration and
Orbital Diagrams
Add to your electrons notes
Draw a line and put today’s date: 11/7 or 11/8
Quantum Mechanical Model
Max Planck and
Werner Heisenberg
expanded upon
Bohr’s model
Bohr
There are energy
levels, but they are
not circular orbits
They are regions
in which you may find
electrons in the
electron cloud
Quantum
Image from the Higher Education Academy Physical Sciences Centre
Electrons are organized in three ways
1st = Energy levels
each atom
contains energy levels;
which generally correspond
to the rows of the PT
It’s like an
address!
2nd = Sublevels
3rd = Orbitals
each energy level
contain sublevels; they
are divided into blocks
called s, p, d and f
each sublevel
contain orbitals; an
orbital is the space
occupied by two (a pair
of) electrons
Electron Sublevels
Sublevel
s
p
d
f
How many
electrons can it
hold?
2 e-
6 e-
10 e-
14 e-
# of orbitals
1
orbital
3
orbitals
Start on
energy
level:
1 and
up
2 and
up
5
7
orbitals orbitals
3 and
up
4 and
up
What do orbitals look like?
orbital on
s sublevel
(one per sublevel)
orbitals on
p sublevel
(three per sublevel)
(remember two electrons
fit in each orbital)
What do orbitals look like?
orbitals on
d sublevel
(five per sublevel)
What do orbitals look like?
orbitals on
f sublevel
(seven per sublevel)
Since sublevels and orbitals are too complicated to
draw all the time, we simplify with orbital diagrams.
Each orbital is represented by a box.
Each electron is represented
by an up or down arrow.

(means 2 electrons)
s sublevel
s sublevel has one orbital,
so we draw one box.
p sublevel
p sublevel has 3 orbitals,
so we draw 3 boxes.
d sublevel
d sublevel has 5 orbitals, so we draw 5 boxes.
f sublevel
f sublevel has 7 orbitals, so we draw 7 boxes.
Orbital and sublevel information
is like a map, telling you where
an electron can be found in an atom.
There are three rules that govern why
an electron will be in one sublevel
rather than another:
1.Pauli Exclusion Principle
2.Hund’s Rule
3.Aufbau Principle
Pauli Exclusion Principle:
No two electrons can have the same set
of quantum numbers (basically, “orbital address”).
What that means is that 2 electrons
may occupy one orbital, but they must have
opposite spin direction.
This is why we draw electrons as arrows facing
opposite directions when they share a box:

Hund’s Rule:
Before 2 electrons will occupy the same orbital
of a sublevel, there must be at least one electron
in every orbital of that sub level.
 
Example: 4
electrons in
a d sublevel
WRONG -This is not stable.
Electrons repel each other.




RIGHT -This is stable.
Hund’s Rule paraphrased –
spread them out before you pair them up!
Aufbau Principle:
Each electron must occupy
the lowest energy orbital available.
Not all sublevels and orbitals have the same energy!
s  p  d  f
energy increases
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p
This chart shows the order that electrons fill sublevels.
Although the d and f sublevels are on lower energy levels,
they have high energy and do not fill until after
the s and p for higher energy levels.
Using the Aufbau Diagram
• Add electrons in the order of the arrows
you drew
• Remember sublevels and electrons
– s holds 2 electrons
– p holds 6 electrons
– d holds 10 electrons
– f holds 14 electrons
The number of columns in each block corresponds
to the number of electrons that fit in that sublevel
You can use the periodic table like a game board
to see the order in which the sublevels fill.
The period
number tells you
the energy level
Each square can
mean the position
of one electron
The block tells you the
sublevels
An element’s location within that block tells you
how many electrons it has in that sublevel
Example: Nitrogen is in the 3rd column of the p block.
It has 3 electrons in the p sublevel
Example: Manganese has 25 electrons. Draw its orbital diagram.
1s
2s
2p
3s
3p
4s
3d
Use Aufbau Principle to determine sublevel and orbital order.
Example: Manganese has 25 electrons. Draw its orbital diagram.

1s


2s

3s

4s


2p



3p





3d
Use Pauli Exclusion Principle to place arrows facing
the opposite direction in each orbital.
Your Turn: Nickel has 28 electrons. Draw its orbital diagram.
1s
2s
2p
3s
3p
4s
3d
• Orbital Notation Practice Website
History of the Periodic Table
More information can be found
in Chapter 6 of your text
Antoine Lavoisier
Image from
Science Shorts
1790 –– He was the first to organize the
elements.
At the time, only 23 elements were known.
He arranged them into a list.
Distinguished metals from nonmetals.
Image by Peter van der Krogt
John Newlands
•
1864 –– At this time, 70 elements were known.
•
The list was too unorganized for that many
elements, so he created a table.
•
He noticed that properties of the elements
repeated every 8 elements when they were
arranged by increasing atomic mass.
•
He called this observation the Law of Octaves.
•
This law was not widely accepted, but it was
mostly correct.
Photo from chemsoc
octave
Predict which element will go here.
H
Li
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
?
octave
H
F
Li
Be
B
C
N
O
Na
Mg
Al
Si
P
S
Cl
octave
Predict which element will go here.
H
Li
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
Cl
?
octave
What does the Newlands Table have in
common with the current periodic table?
H
Li
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
Cl
K
octave
Elements with the same number of Valence
electrons are in the same row.
H
Li
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
Cl
K
Lothar Meyer and Dmitri Mendeleev
Photo from chemsoc
In
1869
Photo from jergym
Czech Republic
They worked on the same type of table,
but not together.
Mendeleev published his ideas first,
so he usually gets the credit.
Lothar Meyer and Dmitri
Mendeleev
He
Li
Be
B
C
N
O
F
They arranged the periodic table by atomic
mass horizontally rather than vertically.
Lothar Meyer and Dmitri
Mendeleev
He
Li
Be
B
C
N
?
Predict which element will go here.
O
F
Lothar Meyer and Dmitri
Mendeleev
He
Ne
Li
Be
B
C
N
O
F
What does the Mendeleev Table have in
common with the current periodic table?
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
Cr
Mn
Columns were arranged so that all elements in a
column have similar chemical and physical
properties.
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
Cr
Mn
What do these three elements have in common?
They are all Noble/ Inert Gases
Lothar Meyer and Dmitri
Mendeleev
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
Cr
Mn
They were able to predict the existence of
undiscovered elements based on blank spaces
in the periodic table.
Henry Moseley
Moseley
observed that
some elements
seemed to be in
the wrong
column based on
their activity.
Photo from chemsoc
Henry Moseley
Fe
55.845
Ru
101.07
Ni
58.693
Rh
102.906
Co
58.933
Pd
106.42
Cu
63.546
Ag
107.868
Os
190.23
Ir
192.217
Pt
195.078
Au
196.967
For example, Nickel reacts more like Platinum.
Moseley decided to order the table
by Atomic Number rather than atomic mass.
26
Fe
55.845
44
Ru
101.07
76
Os
190.23
28
Ni
58.693
45
Rh
102.906
77
Ir
192.217
27
Co
58.933
46
Pd
106.42
78
Pt
195.078
29
Cu
63.546
47
Ag
107.868
79
Au
196.967
Moseley decided to order the table by Atomic
Number rather than atomic mass.
26
Fe
55.845
44
Ru
101.07
76
Os
190.23
27
Co
58.933
45
Rh
102.906
77
Ir
192.217
28
Ni
58.693
46
Pd
106.42
78
Pt
195.078
29
Cu
63.546
47
Ag
107.868
79
Au
196.967
Glen Seaborg
1940 - synthesized Np
and Pu
Decided they must go
in a new block of the
Periodic table called
Actinides.
Seaborg was awarded
a Nobel Prize in
1951.
Review
Who made the first organized
chart of elements?
Antione Laviosier, list of 23 elements
Review
Who made the first chart in Table form?
John Newlands, based on his Law of Octaves
Review
Who first organized the table
in horizontal rows?
Lothar Meyer and Dmitri Mendeleev,
but they did not work together
Review
Who arranged the table the way it is used
today?
Henry Moseley, arranged it by atomic number