1. Electron Configuration
A Closer Look at Electrons

2. Where are they in the Atoms?
Located within energy levels
Energy levels range from 1-7
Higher energy levels
The electron (e-) is farther from the nucleus
The more energy the e- has

3. Within each energy level
There are sublevels that differ by slight differences in energy
There are four sublevels
S, P, D, F
Within each sublevel are paths called Orbitals

4. Orbitals Orbital = a region of an atom which electrons exist.
Each orbital can hold 2 e-
S sublevels, there is 1 orbital, which holds a total of 2 e-

5. Orbitals Cont.
P sublevels, there are 3 orbitals, holding a total of 6 e-
D sublevels, there are 5 orbitals, holding a total of 10 e-
F sublevels, there are 7 orbitals, holding a total of 14 e-

6. What order do orbitals fill?
Orbitals Fill in this order
Number of this type of orbital
Total # of electrons 1s 1 2 2s 2p 3 6 3s 3p 4s 3d 5 10 4p

7. Complete filling order
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

8. Writing The e- configuration
1s2
1 = the energy level
S = the sublevel or orbital
2= the number of electrons

9. How to write an e- configuration
Locate the element on the periodic table.
2. Fill the orbital in the proper order.
3. Check that the total # of e- you have equals the atomic # for that element

10. Practice problems
Write the electron configuration for the following elements
Carbon (C)
Lithium (Li)
Sodium (Na)
Chlorine (Cl)
Potassium (K)
Iron (Fe)