1. Warm-Up Turn in your Flame Test Lab!
How can you determine how many electrons are in an atom?
How do those electrons like to fill up orbitals in an atom?

2. Orbital Notation

3. Aufbau Principle
Electrons fill the lowest available energy orbital before filling higher energy orbitals

4. Pauli Exclusion Principle
In a single atom, two electrons cannot have the same set of 4 quantum numbers

5. Hund’s Rule
When filling degenerate orbitals, each orbital is singly occupied before any orbital is doubly occupied. All electrons in singly occupied orbitals have the same spin.

6. Energy Filling Diagram

7. Hydrogen
Number of Electrons = 1

8. Helium
Number of Electrons = 2

9. Lithium
Number of Electrons = 3

10. Boron
Number of Electrons = 5

11. Carbon
Number of Electrons = 6

12. Oxygen
Number of Electrons = 8

13. Scandium
Number of Electrons = 21

14. Silicon
Number of Electrons = 14

15. Potassium
Number of Electrons = 19

16. Warm-Up Write the orbital notations for the following 3 elements:
I am stamping your Orbital Notation Notes (HW)!
Write the orbital notations for the following 3 elements:
Phosphorus
Magnesium
Krypton

17. Homework Answers

18. Electron Configurations
An abbreviated version of orbital notations
Each sublevel is grouped together!
s holds 2 electrons
p holds 6 electrons
d holds 10 electrons
f holds 14 electrons

19. Examples Nitrogen: 7 electrons Phosphorus: 15 electrons
1s22s22p3
Phosphorus: 15 electrons
1s22s22p63s23p3
Scandium: 21 electrons
1s22s22p63s23p64s23d1

20. Examples Iridium: 77 electrons Xenon: 54 electrons
1s22s22p63s23p64s23d104p65s24d105p6 6s24f145d7
Xenon: 54 electrons
1s22s22p63s23p64s23d104p65s24d105p6
Potassium: 19 electrons
1s22s22p63s23p64s1

21. Examples Cobalt: 27 electrons Silicon: 14 electrons
1s22s22p63s23p64s23d7
Silicon: 14 electrons
1s22s22p63s23p2
Cadmium: 48 electrons
1s22s22p63s23p64s23d104p65s24d10

22. Warm-Up I am stamping your HW!
Write the electron configurations for the following elements:
Hydrogen
Lithium
Potassium
Carbon
Silicon
Tin (Sn)