1. Atomic Structure and the Periodic Table
Section 3.6

2. Using our friend the Periodic Table

3. Creating Energy-Level Diagrams
Begin at lowest energy state (1s) and build from the bottom up until the total number of electrons is reached. *Remember to switch energy levels as needed!
For anions add extra electrons, for cations do an energy level diagram for the neutral atom first and then subtract the number of electrons
No two atoms can have the same series of quantum numbers. If an electron in the same orbital as another electron it must have an opposite spin
No two electrons can be put into the same orbital of equal energy until one electron has been put into each of the equal energy orbital – this is Hund’s Rule

4. Example: Draw the energy diagram for carbon
According to the Aufbau principle we must start at the lowest energy level and build up
We can fit up to two electrons per orbital so applying the Pauli-exclusion principle we must put the arrow beside the first one in the opposite direction

5. Fill the 2s orbital next following the same rules
Now we are in the p orbital, so we need to use Hund’s Rule…fill all orbitals first and then go back again until there are up to six electrons in the p orbital

6. Examples 2 & 3 Draw the energy diagram for magnesium and copper
To do this you must know the order of filling those higher energy orbitals: 1s2s2p3s3p4s3d4p5s4d5p6s4f5d6p etc.
Or use the PT

7. Electron Configurations
It would take forever to always draw energy diagram thus it is better to be able to just write them using symbols
Example:
Write the electron configuration for oxygen
Write the electron configuration for argon
Oxygen has 8 electrons
Argon has 18 electrons

8. Electron Configurations for Ions
Write the electron configuration for the chlorine ion
Write the electron configuration for the sodium ion
Chlorine has 17 electrons Cl-1 has 18
Sodium has 11 electron Na+ has 10

9. Short-form Configurations
Electron configurations can get to be very long so we use a short form where we put the symbol for the noble gas that precedes the atom and continue from there.
Cl can become [Ne]3s23p5
Write the shorthand configuration for tin

10. Seatwork
Pg. 191 #3, 4
Pg. 194 #6-10