1. Electrons: The Bohr Model, Orbitals, and Electron Configuration
Unit 1 Notes

2. Electron Configuration
THREE THINGS NEEDED:
Energy Level
Orbital Type
Number of Electrons

3. ENERGY LEVELS

4. Draw a picture of the Bohr model List one pro and one con of the model

5. Bohr models
Each orbit or energy level is symbolized with the letter n, this is called its principle quantum number

6. Energy Levels
The period (row) in which the element is found in tells us the number of energy levels the atom will have

8. How many energy levels would the following atoms have?
Can you draw them?
Helium Argon Germanium Nitrogen

9. Energy Levels
The atomic number of the element tells us the total number of electrons the atom will have
Remember: Ions will have a different number of electrons due to their charge!

10. Maximum number of electrons
Energy Levels
The energy levels each have a maximum number of electrons they can hold

11. ORBITALS

12. Orbitals Each energy level is made up of different types of orbitals
Orbitals are areas within an atom where electrons are most likely to be found

13. Quantum Model
Erwin Schrödinger used calculus and quantum mechanics to analyze the electrons energy and make a density plot of where the electron will probably be based on their wave-like properties.

14. Quantum Model Schrödinger found
four different recurring shapes when plotting electron density
Each one of these shapes is called an orbital and has a corresponding letter

15. Quantum Model

16. s - Orbitals

17. p - Orbitals 3 types (sublevels)

18. d - Orbitals 5 types (sublevels)

19. f - Orbitals

20. ELECTRONS

21. Orbitals Each energy level is made up of different types of orbitals
Each orbital sublevel can hold two electrons

22. p - Orbitals 3 types (sublevels) 2 e- 2 e- 2 e- 6 e- (full)

23. Electron Configuration
How electrons are organized in the atom
Three parts:
Principal quantum number
(energy level)
Orbital type
Number of electrons in orbital
3s2

24. Electron Configuration
How electrons are organized in the atom
Three parts:
Principal quantum number
(energy level)
Orbital type
Number of electrons in orbital
3s2

25. Electron Configuration
How electrons are organized in the atom
Three parts:
Principal quantum number
(energy level)
Orbital type
Number of electrons in orbital
3s2

26. Electron Configuration
How electrons are organized in the atom
Three parts:
Principal quantum number
(energy level)
Orbital type
Number of electrons in orbital
3s2

27. Electron Configuration and orbital filling diagrams
How to fill up all the energy levels and their orbitals with electrons:
3 Rules

28. Rule 1: Aufbau’s Rule
Electrons start filling with the lowest energy level and fill up from there:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, and 7p

29. Rule 1: Aufbau’s Rule

30. Rule 1: Aufbau’s Rule
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, and 7p

31. Rule 2: Hund’s Rule
Each orbital is made up of its sublevels. One electron occupy must occupy each sublevel before electrons can pair up in a sublevel.

32. Rule 3: Pauli’s Exclusion Principle
Paired electrons must have opposite spins (one spin UP, one spin DOWN)

33. PRACTICE:
Draw the electron configuration and orbital filling diagram for oxygen.

34. Valence Electrons
Valence electrons - The electrons in an atom that are involved in the formation of chemical bonds; These are in the outer energy level.
All remaining electrons in the other energy levels are called the core electrons.

35. Valence Number
The valence number coordinates to the number of valence electrons

36. How many electrons would the following atoms have?
How many of these electrons are valence electrons?
Helium Argon Germanium Nitrogen

37. BOHR MODELS
Draw the electron configuration and orbital filling diagram for phosphorus.

38. Draw the Bohr Model for phosphorus.
BOHR MODELS
Draw the Bohr Model for phosphorus.
STEPS to Drawing Bohr Models:
1) Draw the nucleus (p+ and no)
2) Determine the energy levels by period
3) Fill outer energy level first by the column (valence) number.
4) Fill from inside out until you reach the outer level. This should use all of the electrons.