The Quantum Mechanical Model The nucleus is found inside a blurry “electron cloud” A area where there is a high probability of finding an electron.
The Quantum Mechanical Model
Dec 31, 2015
The Quantum Mechanical Model. The nucleus is found inside a blurry “electron cloud” A area where there is a high probability of finding an electron. Electron Configuration. Principal Quantum Number (n) = the energy level of the electron. (max # e- = 2n 2 ) - PowerPoint PPT Presentation
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The Quantum Mechanical ModelThe nucleus is
found inside a blurry “electron cloud”
A area where there is a high probability of finding an electron.
Principal Quantum Number (n) = the energy level of the electron. (max # e- = 2n2 )
Sublevels- like theater seats arranged in sections (s,p,d,f) (# of sublevels = n )
Within each energy level, the complex math of Schrodinger’s equation describes several shapes.
These are called atomic orbitals - regions where there is a high probability of finding an electron
*No more than 2 electrons in each orbital*
Electron Configuration
Summary
s
p
d
f
# of orbitals
Max electrons
Starts at energy level
1 2 1
3 6 2
5 10 3
7 14 4
sublevel
Electron Configurations
Three main “guiding” principles:
The way electrons are arranged in atoms.
Aufbau principle- electrons enter the lowest energy first.
Electron ConfigurationsPauli Exclusion Principle- at most 2 electrons per orbital
Why only 2 electrons per orbital?like charges repel each other, but…
electrons spin on axis,
clockwise or counterclockwise,
creating magnetic polarization ( ↑↓ )
Hund’s Rule- When electrons occupy orbitals of equal energy (same sublevel ) they don’t pair up until they have to.
- one electron enters each orbital until all orbitals contain one electron with spins parallel.
Writing Electron Configurations(Letter - number designation)
H 1s1
Principle Energy Level
Sublevel
# of e-
Orbital Diagrams
Show each orbital as a circle, box, or line.
Show each electron as an arrow, ↑ or ↓ spin.
Label electron configuration (letter –number).
N 1s 2s 2p
7↑↑ ↑↑ ↑↓ ↓
2 2 3
Incr
easi
ng e
nerg
y
1s
2s
3s
4s
5s6s
7s
2p
3p
4p
5p
6p
3d
4d
5d
7p 6d
4f
5f
Orbital (Aufbau) diagram
ExampleLet’s determine the electron configuration & orbital diagram for Phosphorus
Need to account for 15 electrons
Incr
easi
ng e
nerg
y
1s
2s
3s
4s
5s6s
7s
2p
3p
4p
5p
6p
3d
4d
5d
7p 6d
4f
5f
1s22s22p6 3s23p3
Remember…When we write electron
configurations, we are writing the lowest energy (ground state) configuration.
Do Problems 21-24 pg 160
*** # 21 draw orbital diagrams,
not just e- configurations
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