1. Electron Configuration Orbital Notation Lewis-Electron Dot Diagram
Electrons in Atoms
Electron Configuration
Orbital Notation
Lewis-Electron Dot Diagram

2. 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. 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
Sublevel (block)
# of orbitals
Maximum # of e- S 1 2 p 3 6 d 5 10 f 7 14

5. Examples e- configuration for Oxygen
Oxygen has 8 electrons and is in period 2
1s2
2s2
2p4
6 valence electrons
2 energy level and located in the p-block

6. Practice Write the e- configuration for the following elements: Helium
Neon
Sulfur
Calcium

7. 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

8. 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

9. 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

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

11. Lewis Electron Dot Structure
An atom’s Lewis electron dot structure consists of :
element’s symbol-which represents the atomic nucleus and inner-level electrons, surrounded by dots representing the atom’s valence electrons.
Source: Glencoe Chemistry Matter and Change pg. 140

12. How do we use the periodic table to draw
Group 1A:
1 valence electron
Group 3A:
3 valence electrons
Group 4A:
4 valence electrons
Group 5A:
5 valence electrons
Group 6A:
6 valence electrons
Group 7A:
7 valence electrons
Group 8A:
8 valence electrons
Group 2A:
2 valence electrons
How do we use the periodic table to draw
Lewis electron dot structures?
Identifying the representative group
number will allow you to determine
the number of valence electrons.
Here’s how….

13. Writing out Lewis Electron Dot Structure
Group # = number of valence electrons
Example: Phosphorus is on group 5A, so it has 5 valence electrons.
Step 3: Continue placing one electron on each of the four sides of the symbol & then pair up the electrons until you have placed all valence electrons around the symbol
Step 1: write the element symbol P
Step 2: Start at the top of the symbol and place one electron

14. Practice
Write the Lewis Electron Dot Structure for the following elements:
Helium
Neon
Sulfur
Calcium

15. Questions??