1. Electrons in the Atom

2. What do we know about electrons?
What is the basic information about electrons (charge, mass, location)?
Explain the Bohr model structure. Draw a model for carbon. Label the valence electrons. Draw a Lewis dot structure for carbon.
What is the energy released when a hydrogen electron moves from n=6 to n=2?
What is the difference between ground state and excited state? How do electrons move between these two states?
What does it mean for an atom to become an ion? How does the charge relate to the change in electrons?

3. Quantum Mechanics
Using a mathematical description of the wavelike behavior of particles on the atomic level
Electrons are located in orbitals (spaces where they have a high probability of being found)
Each orbital is described by three quantum numbers

4. Atomic Orbitals
Region of space in which there is a high probability of finding an electron
Principal quantum number, n
Angular momentum quantum number l
Magnetic quantum number ml

5. Principal Energy levels
Quantum number, n
Orbitals with the same value of n are in the same shell
n= 1, 2, 3, 4, etc.
Energy level n
Max number electrons 1 2 8 3 18 4 32

6. Angular Momentum quantum number l
Orbitals with the same value of n and l are in the same subshell
Different shaped spaces within the sublevels
s is spherical (1 orbital)
p is dumbbell (3 orbitals)
d varies (5 orbitals)
f more complex (7 orbitals)
(2 electrons per orbital)

9. Summary of Principal Energy Levels, Sublevels, and Orbitals
Energy level n
Number of sublevels
Type of sublevel 1 1s 2
2s, 2p 3
3s, 3p, 3d 4
4s, 4p, 4d, 4f

10. Magnetic quantum number ml
Distinguishes orbitals of given n and l, of given energy and shape but having different orientation in space
Values are integers from -1 to +1

11. Magnetic quantum number ms
Refers to the two possible orientations of the spin axis of an electron
Values are +1/2 and -1/2
Each orbital can contain two electrons with opposite spins
“Up”
“Down”
Spintronics

12. Keeping Track of Electrons
All this information about electrons is very hard to visualize and understand
Electron configuration and orbital diagrams can help
Electron configuration: description of the orbitals occupied by electrons

13. Three rules and electron configuration
Aufbau Principle-
Pauli Exclusion Principal –
Hund’s Rule –
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14. Three rules and electron configuration
Aufbau Principle- fill lowest energy level first
Pauli Exclusion Principal – 2 electrons per orbital with opposite spin
Hund’s Rule – Bus Seat, electrons occupy orbitals in the same energy level going in the same spin direction
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15. Energy Levels & Orbitals
Sublevels
Energy Levels
Orbitals 16

16. Aufbau diagram

17. Orbital diagram

18. Electron configuration
1s22s22p63s1
Sodium

20. Electron Configuration Video
Periodic Table Song