1. Ch. 5 Electron Configurations

2. Orbitals: 3D representation of electrons pathways

3. 1s2 Energy Levels Represented by numbers, from 1-7.
1 = lowest energy = highest energy
When writing electron configurations, the order is
Energy level, orbital shape, # of electrons
Energy Level
1s2
Number of Electrons
Orbital Shape

4. Diagonal Rule: Follow the Arrows

5. Counting Electrons in each Orbital
Next to each letter (s, p, d, or f) we write the number of electrons as a superscript.
Orbital
Max # of Electrons s 2 p 6 d 10 f 14
Which element is represented by these electron configurations?
1s1 H
1s He
1s22s1 Li
1s22s22p2 C
1s22s22p63s2 Mg

6. Check for Understanding
Write the electron configurations for the following elements:
Element
Electron Configuration
Total # of Electrons He
1s2 2 C
1s22s22p2 6 Ne
1s22s22p6 10 Ca
1s22s22p63s23p64s2 20 Ag
1s22s22p63s23p64s23d104p65s24d9 47

7. Abbreviated configurations
Step 1: Use elements on very right of periodic table.
Step 2: Write rest of configuration
Example:
Ca: [Ar] 4s2 Ne: [He] 2s22p6
Cu: [Ar] 4s23d9 Zr: [Kr] 5s24d2