1. Electron Configuration and Periodic Trends

2. Essential Question
How do Aufbau’s Principle, the Pauli Exclusion Principle, and Hund’s Rule dictate the arrangement of electrons in an atom

3. Electron Configuration
The arrangement of electrons in an atom is its electron configuration
Every element will have a unique electron configuration because they all have different numbers of electrons

4. Ground State Electron Configuration
Electrons in an atom tend to assume arrangements that have the lowest possible energies. This is called the electrons ground state electron configuration.

5. Rules Governing Electron Configuration
Aufbau Principle states that an electron occupies the lowest energy orbital that can receive it.

6. Rules Governing Electron Configuration
Pauli Exclusion Principle states that for two electrons to occupy the same orbital, they must have opposite spin states

7. Rules Governing Electron Configuration
Hund’s Rule states that orbitals of equal energy are occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state.

8. Arrangement of The Atom
All atoms are made up of :-
Principle energy levels (periods on the periodic table) represented by n=1
Each principle energy level contains sublevels (S, P, D, F)
Each sublevel contains orbitals (S-1, P-3, D-5, F-7)
Each orbital can hold a maximum of 2 electrons
Sublevels
Orbitals
Maximum
Electrons S 1 2 P 3 6 D 5 10 F 7 14

9. Writing Electron Configuration

10. Writing Electron Configuration
Draw the electron configuration chart and use it to write the unabbreviated electron configurations for the following elements.
Lithium
Aluminum
iron

11. Writing Electron Configuration
Draw the electron configuration chart and use it to write the abbreviated electron configurations for the following elements using the noble gas notation.
Lithium
Aluminum
iron

12. Determining Elements from Electron Configurations
Use the electron configuration to determine the names of the elements.
1s22s22p63s23p4
[Xe]6s24f145d6

13. Writing Electron Configuration

14. Writing Electron Configuration
Use the periodic electron configuration chart and use it to write the unabbreviated electron configurations for the following elements.
Lithium
Aluminum
iron

15. Writing Electron Configuration
Use the periodic electron configuration chart and use it to write the abbreviated electron configurations for the following elements using the noble gas notation.
Lithium
Aluminum
iron