Electron Configuration Notation with Atomic Structure Review Chemistry I Mr. Streeter.
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Transcript of Electron Configuration Notation with Atomic Structure Review Chemistry I Mr. Streeter.
Electron Configuration Notation with Atomic Structure Review
Chemistry IMr. Streeter
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 e- behave like waves based on Bohr’s model.-This was explained in the electromagnetic spectrum.
The frequency is mathematically related to the wavelength:c=λv
Where c=speed of light (3.0 x 108 m/s)λ= wavelength v= frequency
Electromagnetic Spectrum
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
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
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
n= level number (n=1 thru 7). (n-1)= Shape and type of orbital
s=0p=1d=2f= 3
m (from – ,0,+)=Magnetic quantum numberms= Magnetic spin. Only have two possible numbers (+1/2 and -1/2)
Quantum Numbers
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
Types and shapes of orbitals
Electron configuration
Aufbau principle -Electron fill lowest energy levels first.
Ex. 1s<2s<2p<3s<3p
Electron configuration
NotationsThere are 3 notations:1) Long notation or electron
configuration1s22s22p6
2) Orbital Notation
s1
s2
Electron configuration
3) Shorthand Notation or Noble Gas configuration.
[Ne]3s23p4
Electron configuration
Hund’s Rule -For atoms in ground state, the number of unpaired electrons is the maximum possible and have the same spin.
Order in which subshells are filled with electrons
1s
2s
3s
4s
5s
6s
7s
2p
3p
4p
5p
6p
3d
4d
5d
6d
4f
5f
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
pss 221
Filling Rules for Electron Orbitals
Aufbau Principle: Electrons are added one at a time to the lowest energy orbitals available until all the electrons of the atom have been accounted for.Pauli Exclusion Principle: An orbital can hold a maximum of two electrons. To occupy the same orbital, two electrons must spin in opposite directions.Hund’s Rule: Electrons occupy equal-energy orbitals so that a maximum number of unpaired electrons results.
*Aufbau is German for “building up”
General Rules
Pauli Exclusion Principle Each orbital can hold TWO electrons
with opposite spins.
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
General Rules
Aufbau Principle Electrons fill the
lowest energy orbitals first.
“Lazy Tenant Rule”
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
2s
3s
4s
5s
6s
7s
1s
2p
3p
4p
5p
6p
3d
4d
5d
6d
4f
5f
1s
2s
2p
3s
3p
4s
4p
3d
4d5s
5p6s
7s
6p
6d
4f
5f
5d
Energ
y
RIGHTWRONG
General Rules Hund’s Rule
Within a sublevel, place one electron per orbital before pairing them.
“Empty Bus Seat Rule”
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
O 8e-
Orbital Diagram
• Electron Configuration
1s2 2s2
2p4
Notation
1s 2s 2p
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
O15.9994
8
• Shorthand Configuration
S
16e-Valence ElectronsCore Electrons
S 16e- [Ne] 3s2 3p4
1s22s22p63s23p4
Notation
Longhand Configuration
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
S32.066
16