Electron Configuration

1
Electron Configuration

• Mapping the electrons

2
Electron Configuration

• The way electrons are arranged around the nucleus.

3
Quantum Mechanical Model

• 1920s
• Werner Heisenberg (Uncertainty Principle)
• Louis de Broglie (electron has wave properties)
• Erwin Schrodinger (mathematical equations using
  probability, quantum numbers)

4
Heisenberg uncertainty principle

• it is impossible to determine simultaneously both
  the position and velocity of an electron or any
  other particle with any great degree of accuracy
  or certainty.

5
Erwin Schrodinger

• Formulated equation that describes behavior and
  energies of subatomic particles.
• Incorporates both particle and wave behavior in
  terms of wave function
• is proportional to the probability of
  finding an electron.
• Leads to Quantum Mechanics we cannot pinpoint an
  electron in an atom but we can define the region
  where electrons can be in a particular time
  called a Probability map.a 3-dimensional area in
  space called an ORBITAL

6
Principal Quantum Number, n

• Indicates main energy levels
• n 1, 2, 3, 4
• Each main energy level has sub-levels

7
Energy Sublevels

• s p d f g

8

• The principle quantum number, n, determines the
  number of sublevels within the principle energy
  level.

9
Orbital Quantum Number, l(Angular Momentum
Quantum Number)

• Indicates shape of orbital sublevels
• l n-1
• l sublevel
• 0 s
• 1 p
• 2 d
• 3 f
• 4 g

10
Orbital

• The space where there is a high probability that
  it is occupied by a pair of electrons.
• Orbitals are solutions of Schrodingers equations.

11
Orbitals
12
Visualizing the orbitals
13
Orbitals in Sublevels

• Sublevel Orbitals electrons
• s 1 2
• p 3 6
• d 5 10
• f 7 14
• g 9 18

14
Three rules are used to build the electron
configuration

• Aufbau principle
• Pauli Exclusion Principle
• Hunds Rule

15
Aufbau Principle

• Electrons occupy orbitals of lower energy first.

16
Orbital Diagram
17
Filling Order diagram
18
-Pauli Exclusion Principle(Wolfgang Pauli,
Austria, 1900-1958)-Electron Spin Quantum Number

• An orbital can hold only two electrons and they
  must have opposite spin.
• Electron Spin Quantum Number (ms)
• 1/2, -1/2

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Hunds Rule

• In a set of orbitals, the electrons will fill the
  orbitals in a way that would give the maximum
  number of parallel spins (maximum number of
  unpaired electrons).
• Analogy Students could fill each seat of a
  school bus, one person at a time, before doubling
  up.

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Orbital Diagram for Hydrogen
21
OrbitalDiagram for Helium
22
Orbital Diagram for Lithium
23
Orbital Diagram for Beryllium
24
Orbital Diagram for Boron
25
OrbitalDiagram for Carbon
26
Orbital Diagram for Nitrogen
27
Orbital Diagram
28
Notations of Electron Configurations

• Standard
• Shorthand

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Orbital Diagram for Fluorine
30
Standard Notation of Fluorine
Number of electrons in the sub level 2,2,5
1s2 2s2 2p5
Main Energy Level Numbers 1, 2, 2
Sublevels
31
Shorthand Notation

• Use the last noble gas that is located in the
  periodic table right before the element.
• Write the symbol of the noble gas in brackets.
• Write the remaining configuration after the
  brackets.
• Ex Fluorine He 2s2 2p5

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Blocks in the Periodic Table