1. Warm Up: Rubidium has two common isotopes, 85Rb and 87Rb
Warm Up: Rubidium has two common isotopes, 85Rb and 87Rb. If the abundance of 85Rb is 72.2% and the abundance of 87Rb is 27.8%, what is the average atomic mass of rubidium?
Today: Orbital Diagram and Electron Configuration Notes and Practice
Homework: Finish Practice

3. ENERGY LEVEL (n) 2 8 18 “Rings” of Bohr’s planetary model
7 possible energy levels
Maximum number of electrons in each energy level = 2n2
1st level:
2nd level:
3rd level: 2 8 18

6. Summary (energy levels, sublevels)1 s 2
s, p 3
s, p, d 4
s, p, d, f 5 6 7

7. Summary (sublevels, orbitals, electrons)
max # electrons
Orbital diagram s 1 2 p 3 6 d 5 10 f 7 14

8. MAGNETIC SPIN
“Spin up”
“Spin down”

9. RULES FOR ELECTRONS An orbital can hold a maximum of TWO electrons
Pauli exclusion principle
Aufbau principle
Hund’s rule

10. Pauli Exclusion Principle
no two electrons can have the same “address”
Energy level
Sublevel
Orbital
Spin

11. Aufbau Principle
Electrons will fill the orbitals with the lowest amount of energy before filling in orbitals that have more energy
Order is: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

13. Hund’s Rule
Electrons will not share an orbital of the same energy if there is an empty orbital with that energy is available

14. Draw an orbital diagram for carbon:1s 2s 2p

15. How to draw orbital diagrams
Use periodic table to figure out where to end (energy level and sublevel of last electron)
Draw boxes (orbitals) for all energy levels and sublevels up to the ending point
1 box for s, 3 boxes for p, 5 boxes for d, 7 boxes for f
Fill boxes with electrons (2 per orbital) with opposite spins
Follow Hund’s rule when in the p, d, or f sublevels

16. Electron configurations
Based on orbital diagrams
Use numbers and superscripts along with s, p, d and f to show location of electrons in atoms
Coefficient = energy level
Letter = sublevel
Superscript = # of electrons in sublevel

17. Example:
Energy level 2 electrons
1s2
sublevel

18. Write an electron configuration for nitrogen:1s 2s 2p

19. Practice 1s22s22p4 Draw the orbital diagram for oxygen
Write the electron configuration for oxygen 1s 2s 2p
1s22s22p4

21. Shortcuts!! [Ar] 4s23d104p5b Shortcut (shortened) Notation:
Use closest Noble Gas before the element
For bromine:
Closest Noble Gas before the element:
Argon:
Shortcut Notation:
[Ar] 4s23d104p5b

22. What is the electron configuration of potassium?
1s22s22p63s23p63d1
1s22s22p23s23p24s1
1s22s22p63s23p3
1s22s22p63s23p64s1

23. Each period number in the periodic table corresponds to _______. A)
Each period number in the periodic table corresponds to _______ A) an atomic mass B) an energy level
C) an energy sublevel D) an atomic number