Anion vs. Cation
are
Cations are ions with aCations
net positive
charge.
pawsitive
Ag+, H3O+, and NH4+
Anions are ions with a net negative charge.
OH-, O2-, and SO42-
Heisenberg Uncertainty Principle
You can't know with 100% certainty
where an electron is and where it's
going next.
Heisenberg and the Atomic Bomb
• Codename: Operation Epsilon
– Allied Forces secured, by MI6, 10 German
scientists who they thought might be developing
the first German atomic bomb.
• Werner Heisenberg
• Otto Hahn
Electron Subshells
• Within each energy (or quantum) level, there
are also sublevels (or types); s, p, d, and f
• These sublevels have distinct shapes and
energies (s<p<d<f)
Quantum level / Row
Sublevels types
1
2 and 3
4 and 5
s
s and p
s, p, and d
6 and 7
s, p, d, and f
Electron Subshells
The higher level,
the more
sublevels it has
s orbitals (s for sphere)
1s
2s
3s
Three p Orbitals (p for peanut)
px
pz
py
d orbitals (d for donut)
f orbitals (f for funky)
Electron Orbitals
• Each sublevel contains a set number of
orbitals
• An orbital is the area around a nucleus where
an electron is most likely found.
• Chemical behavior of an atom is determined
by the number and arrangement of its orbitals
s p d f Blocks
Electron Orbitals
Each orbital can hold up to 2 electrons
Sublevel (type)
# of orbitals
Maximum number of e-
s
p
d
f
1
3
5
7
2
6
10
14
• Electrons exist in sublevels (s p d f)
o Rank in Energy (s<p<d<f)
o Shapes of these sublevels
• The location of these sublevels
on the Periodic Table
• Each sublevel contains a set number of Orbitals
o Each orbital can hold ONLY 2 electrons
• (s=1, p=3, d=5, f=7)
Orbitals and Energy
• As you move up energy levels (going from
Rows 1 through 7) the orbitals become larger
because the electrons are farther and farther
from the nucleus.
• As you move away from the nucleus, the
amount of energy needed to maintain the
orbital becomes greater.
THREE RULES
These are extremely important!
The Aufbau Principle
• Each electron occupies the
lowest energy orbital (~1920)
– i.e. Electrons are Lazy!
• You have to beat LV 1 in COD before
you move to LV 2
• All orbitals related to an energy
level are of equal energy.
– i.e. The three 2p orbitals are the
same energy level.
Pauli Exclusion Principle
• A maximum of two electrons may occupy a
single orbital, but only if the electrons have
opposite spins. (1925)
– These spins are called “spin up” and “spin down.”
OR
Hund’s Rule
• Single electrons with the
same spin must occupy
each possible orbital before
additional electrons with
opposite spins can occupy
the same orbitals. (~1927)
– i.e. Electrons are unfriendly!
Also lived to be 101 years
old, discovered quantum
tunneling, and co-found
MO Theory (1966)
• Would you sit with a total
stranger at a restaurant?
Short, Sweet, and to the Point
• Aufbau
– You have to fill the lowest orbitals first
• Pauli
– You can only have two electrons per orbital
• Hund
– You have to fill all the empty orbitals before you
double up
Bellwork: 2 min
• Complete the
orbital diagram
for Ni
(element 28)
BellWork: 2 min
• Using a Periodic Table and the Figure 3-1 below, tell
me what element I am referring to if I tell you the
electron configuration is
1s22s22p63s23p64s23d8
Electron Configurations
Electron Configurations
s1 s2
1
2
3
4
5
6
7
p1 p2 p3 p4 p5 p6
d1 d2d3d4d5d6d7 d8 d9 d10
f1 - f14
Electron Configurations
• Electron configurations
• represent how the electrons are distributed in the
atom
• describe where the electrons are and what energy
they possess
Electron Configurations
• Start at the lowest level and work out (like
how you read a book)
• The order of filling orbitals is:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p,
5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s,
5f, 6d, 7p, 6f, 7d, 7f
• How are you supposed to remember this?
Example
Sulfur has 16 electrons
–
–
–
–
–
The first 2 go into the 1s orbital- 1s2 > 14 left
The second 2 go in the 2s orbital- 2s2 > 12 left
Next is the 2p orbital, it holds 6- 2p6 > 6 left
Next is the 3s orbital, it holds 2- 3s2 > 4 left
The last 4 go into the 3p, but do not fill it up- 3p4
– So our electron configuration is..
2
1s ,
2
2s ,
6
2p ,
2
3s ,
4
3p
Writing Electron Configurations
H
1s1
He
1s2
Li
1s2
2s1
C
1s2
2s2
2p2
S
1s2
2s2
2p6 3s2
3p4
Using the periodic table, write the complete
electronic configuration for each:
A. Cl
1s2 2s2 2p6 3s2 3p5
B. Sr
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
C. I
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
Exit Slip: 2 min
• Using a Periodic Table and the Figure 3-1 below, tell
me what element I am referring to if I tell you the
electron configuration is
1s22s22p63s23p64s23d104p65s24d105p2
BellWork: 2 min
• What is the electron configuration for tin (Sn #50)?
(FUN FACT! There are two allotropes of tin- gray tin and
white tin- each with very different properties)
1s22s22p63s23p64s23d104p65s24d105p2
Noble Gas Electron Configuration
He Ne Ar
Kr Xe Rn
Noble Gas Electron Configuration
A. Cl
1s2 2s2 2p6 3s2 3p5
B. Sr
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
C. I
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
Noble Gas Electron Configuration
A. Cl
1s2 2s2 2p6 3s2 3p5
B. Sr
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
C. I
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
Noble Gas Electron Configuration
A. Cl
[Ne] 3s2 3p5
B. Sr
[Kr] 5s2
C. I
[Kr] 5s2 4d10 5p5
Try This!!!!
Short and Long Hand Electron Configuration for
Potassium (K #19)
1s2 2s2 2p6 3s2 3p6 4s1
[Ar] 4s1