1. Electrons in Atoms Electron Configuration Orbital Notation
Essential question: What correlation is there between electron configuration and orbital notation?

2. Electron Configuration
Essential question: What correlation is there between electron configuration and orbital notation?
Electron Configuration
A form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels
Example of e- configuration for Hydrogen:
1s1
Total # of electrons in that sublevel. 1st column of s-block
S-Block
Principle Quantum number which stands for the energy level

3. Periodic Patterns Yellow represents the s-block
Pink represents the p-block
Green represents the d-block
Orange represents the f-block
S-block
S-block
d-block
p-block
f-block

4. Learning Check
What element would have an electron configuration ending in 4s1?
Potassium

5. Order of filling sublevels
1s2 2s2 2p6 3s2 3p6 4s2
You must fill in each sublevel with its maximum number of electrons before you move to the next energy level (Aufbau Principle)
Sublevel (block)
# of orbitals
Maximum # of e- S 1 2 p 3 6 d 5 10 f 7 14

6. Examples e- configuration for Oxygen
Oxygen has 8 electrons and is in period 2
1s2
2s2
2p4

7. Practice Write the e- configuration for the following elements:
Helium
Sulfur
Calcium
Valence electrons are the electrons on the outermost (highest) energy level.
Place a box around the valence electrons in the examples above.

8. Nobel Gas Electron Configuration
Shows the energy levels and sublevels of the valence electrons and any d or f electrons.
In Nobel Gas Configurations – the last Nobel gas on the periodic table BEFORE the element of interest is placed in brackets to represent the core electrons. The Nobel gas is then followed by the valence electrons and any electrons from the d or f subshells.

9. Examples Noble Gas Electron Configuration for Oxygen
[He]2s22p4
Nobel Gas Electron Configuration for Iron
[Ar]4s23d6
*NOTE- If asked to give the electron configuration of a Nobel gas you cannot use Nobel gas configuration – you must use standard electron configuration.

10. Practice
Write the Noble gas electron configuration for the following elements:
Sulfur
Calcium
Bromine

11. Orbital Notation Every box represents an orbital
Sublevel (block)
# of orbitals
Maximum # of e- S 1 2 p 3 6 d 5 10 f 7 14
Every box represents an orbital
Every arrow represents electrons

12. General Rules Pauli Exclusion principle Hund’s rule
Every orbital can only hold 2 electrons with opposite spins
Hund’s rule
Within a sublevel, place one e- per orbital before pairing them.
Right
WRONG

13. Example: Orbital Notation for Oxygen: Remember:
1s2
2s2
2p4
Orbital Notation for Oxygen:
You know the e- configuration for oxygen is 1s22s22p4
Remember:
Every orbital is represented by a box
Every orbital holds a maximum of 2 electrons
s-block represented by 1 orbital
p-block represented by 3 orbitals

14. Practice Show orbital notation for the following elements: Helium
Sulfur
Calcium