Orbital Filling

1
Orbital Filling

• Where do these electrons go?

2
Aufbau Principle

• Orbitals are filled from lowest energy to highest
  energy
• Orbitals closest to the nucleus contain lower
  energy
• They are filled first

3
Orbital Energies Lowest to Highest (p. 147)
4
Orbital Diagrams

• Shows the distribution of electrons within
  orbitals
• Circles/Lines are used to represent the different
  orbitals
• Arrows are used to represent single electrons

5
Orbital Diagrams for

• Hydrogen
• Helium
• Pauli Exclusion Principle
• Each orbital can only contain two electrons
• These electrons must be distinguished from one
  another (opposite spin)
• One arrow up, One arrow down
• Lithium

6
Orbital Diagrams for

• Boron
• The first p sublevel
• When the sublevels are drawn, all orbitals within
  that sublevel must be drawn
• Carbon
• Hunds Rule
• Electrons will not pair up within orbitals until
  each orbital within a sublevel contains at least
  one electron
• Electrons distribute evenly

7
Orbital Diagrams for

• Neon
• All orbitals within the highest sublevel are
  completely filled
• These elements are chemically stable (Noble
  Gases)
• Sodium
• Noble Gas notation
• The lower filled sublevels can be represented by
  writing the symbol for the previous Noble Gas in
  brackets ( Ne )

8
Orbital Diagrams for

• Phosphorus
• Hunds Rule
• Argon
• Completely filled sublevel
• Potassium
• Noble Gas notation
• Aufbau Principle
• Lowest energy orbitals filled first
• 4s orbitals have lower energy that 3d
• They are filled first

9
Orbital Diagrams for

• Manganese
• Aufbau Principle
• Lowest energy orbitals filled first
• 3d orbitals have higher energy that 4s, but lower
  than 4p
• Hunds Rule
• Hunds Rule applies to all sublevels
• There are five d orbitals
• Each one will receive one electron before any are
  paired
• There are exceptions to this rule within
  transition metals, but the concept is applied
  here for practice

10
Orbital Diagrams for

• Arsenic
• Aufbau Principle
• Hunds Rule

11
Electron Configurations

• A short hand way of representing the location
  of electrons around the nucleus
• Not as much detail as orbital diagrams, but a
  convenient way of showing patterns for groups of
  elements on the periodic table

12
Electron Configurations for

• Hydrogen
• Helium
• Lithium
• Boron
• Carbon
• Nitrogen
• Neon
• Sodium
• Noble Gas notation

• Phosphorus
• Argon
• Potassium
• Aufbau Principle
• Noble Gas notation
• Manganese
• Aufbau Principle
• Arsenic

13
Patterns in Electron Configurations

• All elements within the same column have the same
  ending for their electron configuration
• All end with electrons in the same sublevel, but
  different principle energy level
• These elements all belong to the same family or
  group
• They exhibit similar chemical properties
• Due to their similar electron configurations,
  which will be discussed in more detail in later
  chapters

14
Groups of Elements Electron Configurations