You will learn how to write:
electron configuration
noble gas configuration
orbital configuration
Lewis Dot
You will learn the principals of:
Aufbau
Hund’s
Pauli Exclusion
ws.5.1,5.2.5.3,5.4, 5.5
QUANTUM MECHANICS
It’s all about electrons
Only electrons are involved with chemical reactions
Review electron: location charge symbol
Quantum # tell you 4 things:
l. Main energy level
2. shape of orbit
3. orientation
4. spin
Principle Quantum #: energy level of electron indicates distance from nucleus
) 2 ) 8 ) 18 ) 32 )
2N2
ENERGY INCREASES AS ATOM GET BIGGER
Principle quantum number represented by
2n2
7 periods on PT
7 energy levels for e-
Calculate #e- using 2n2
N represents energy level
Angular Momentum Quantum #
Indicates shape of orbit
s
p
d
f
S (can hold) 2e-
P (can hold) 6e-
D (can hold) 10e-
F (can hold) 14e-
Now that you have learned principle quantum number and angular momentum
quantum number you can now learn to write
“ Electron Configuration”
2 ) 8 ) 18 ) 32 )
1s2 ) 2s2 2p6 ) 3s2 3p6,3d10 ) 4s2 4p6 4d10 ) 5s2 5p6 5d10
B
O
Al
Aufbau Principle : an e- will occupy lowest level of energy available
4s2 will fill before 3d10
1s2 ) 2s2 2p6 ) 3s2 3p6, 4s2 3d10 4p6 5s2 4d10 5p6…
Cobalt
Krypton
Silver
Noble Gas Notation
Did you notice how you had to write the first few electron configurations over and over?
Uck!!! Simplify using Noble Gas Notation
On periodic chart elements on far right are called … noble gases
He
Ne
Ar
Kr
Xe
Rn
The have
nice complete
energy levels
with no e- left
over.
They do not
react with
anything.
Magnetic Quantum # …orientation…x y z
1s2 , 2s2 2p6
px , py , pz
1s2, 2s2 2p6, 3s2 3p6 4s2, 3d10
dx2y2, dxy, dyz, dxz, dz2
Spin Quantum # … which way e- spins – ½ +½
Orbital Notation
Hund’s principle: orbitals of equal energy are each
occupied by one e- before any orbitals are
occupied by a 2nd e-.
Orbital notation shows magnetic & spin quantum #
Boron
Phosphorus
Chromium
3 rules governing electron
configuration
Aufbau Principle
Hund’s Principle :
Pauli’s Exclusion Principle:
.
Hund’s Principle:
• Orbital's of equal energy are occupied by one electron before
any orbital is occupied by a second electron
• and all electrons in single occupied orbital's must have the
same spin.
Pauli’s Exclusion Principle:
No two electrons in the same atom
can have the same set of four quantum numbers.
3 methods to represent electron locations
1. Electron configuration
2. Noble Gas configuration
3. Orbital Notation
Fourth and final….
Lewis Dot configuration
Lewis Dot configuration Valence electrons: electrons in outer energy level.
**** only outside electrons involved in Chemical Reactions****
B
O
Al
K
Cl
There is a secret=== group # tells valence electrons
Ws. 5.5 Lewis Dot
1. Carbon
2. Nitrogen
3. Phosphorus
4. Sulfur
5. Aluminum
6. Krypton
7. Calcium
8. Sodium
9. Potassium
10.Fluorine
11.Silicone
12.Bromine
13.Beryllium
14.Sulfur
15.Chlorine