This document discusses electron configuration and how electrons are arranged in atoms. It introduces the Bohr model of electron shells and energy levels, then describes more accurate quantum mechanical models of electron orbitals. The document explains the Aufbau principle of filling orbitals from lowest to highest energy, the Pauli exclusion principle of maximum two electrons per orbital, and Hund's rule of filling orbitals within the same level. It outlines the shapes and notations of s, p, d, and f orbitals and how they relate to the periodic table and electron configuration notation.

1. Mrs. Nading
Conceptual Chemistry A

2. What is Electron Configuration?
 What do we know about electron
configuration now?
- Electron Cloud
- Bohr Model
- Need a more accurate way of
diagraming/configuring where electrons
go in an atom

3. The Bohr Model
 Spherical Organization
 Energy Levels
 Electrons can increase or decrease in
energy by moving from one level to
another.
 Giving off energy-
Moving down a level
 Absorbing Energy –
Moving up a level

4. Orbitals

5. The Aufbau Principle
 Aufbau – German for ‘Filling Up’
 Electrons fill order from low to high
energy

6. Pauli Exclusion Principle
 Each Orbital can only contain 2
electrons
 They must be facing opposite directions

7. Hunds Rule
 If there is more than one orbital at the
same energy level, they fill one by one
before pairing.

8. What are these energy levels
you speak of?
 Remember: Bohr Model, the levels are
represented spherically
 With Orbitals, the energy levels are
represented in different shapes and
sizes
 Orbitals have shapes

9. The S orbital – holds 1 pair of electrons
 How we see it
 How we write it

10. P-Orbital – Holds 3 pairs of electons
 How it looks
 How we write it

11. D-Orbitals – Can hold 5 electron
pairs
 How they look
 How we write them

12. F-Orbitals – Can hold 7 electron
pairs
 How they look
 How we write them

13. How our Energy Levels are
arranged

14. Remember our Periodic Table?

15. How do we apply this
information?
 Where do we start?
 Step one – Pick an element
 Step two – Figure out how many
electrons that element has
 Step three – draw out or refer to your
aufbau diagram
 Step 4 - Fill the electron shells
systematically

16. We need to combine some Info
 We need to combine our orbital notation
with our Energy level arrangement.

17. Let’s try it
 H
 S
 Mn