Transcript Electron Configuration

Electron Configuration
Chemistry I
Mr. Pena
Bohr’s Atom Model
-Confines electrons in shells
-Electrons loses energy due to
movement.
-Electrons can be in certain levels
depending of the energy they have.
-The region where we can find the
electron with high probability is called
the orbital.
Nature of the electron
-Thompson’s work show that e- behave
like particles.
-In 1924, Louis de Broglie states that ebehave like waves based on Bohr’s
model.
-This was explained in the
electromagnetic spectrum.
Electromagnetic Spectrum
The frequency is mathematicaly related to the
wavelenght:
c=λ﹒v
Where c=speed of light (3.0 x 108 m/s)
λ= wavelenght
v= frequency
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Electromagnetic Spectrum
All the frequencies or wavelenghts of
electric radiation.
Electromagnetic Spectrum
-The movement of electrons produced light
when received and release energy.
-In 1905, Albert Einstein proposed that light
have properties of light and waves.
Light Emission
Light Emission
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Electron in lowest possible energy is in
ground state.
Electron that gains energy move to excited
state.
Electron release energy as go back to ground
state.
Light Emission
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E1=Energy in ground state
E2=Energy in excited stated.
Overall energy= E1-E2
Quantum Numbers
-Number that specifies the properties of
the electrons.
-There are 4 quantum numbers: n, , m
and ms
Quantum Numbers
n= level number (n=1 thru 7).
 (n-1)= Shape and type of orbital
s=0
p=1
d=2
f= 3
m (from – ,0,+)=Magnetic quantum number
ms= Magnetic spin. Only have two possible
numbers (+1/2 and -1/2)
Electron configurations
-Arrangements of electrons in an atom.
-Each orbital can have only 2 electrons and
with different quantum numbers. This is
known as Pauli exclusion principle.
Electron configuration
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Types and shapes of orbitals
Electron configuration
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Aufbau principle -Electron fill lowest energy
levels first.
Ex.
1s<2s<2p<3s<3p
Electron configuration
Notations
There are 3 notations:
1) Long notation or electron configuration
1s22s22p6
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2) Orbital Notation
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1s
2s
Electron configuration
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3) Shorthand Notation or Noble Gas
configuration.
[Ne]3s23p4
Electron configuration
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Hund’s Rule -For atoms in ground state, the
number of unpaired electrons is the
maximum possible and have the same spin.
Electron configuration
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Orbital Filling Order (Diagonal Rule)
Electron configuration
Example
What is the electron configuration of an
element with atomic number of 9 (Z=9)
An element with z=9 is Fluorine.
We start with the less energy level and
orbital, so then is 1s22s22p5. The orbital
notation will be then
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1s 2 s
2p