1. Electron Configurations Write the orbital type and energy level with superscripts for the number of electrons they contain.

2. Electron Configurations Example: Carbon

3. Electron Configurations Need to Know: Period numbers of periodic table are the energy levels (n) of the orbitals Regions of periodic table where certain “clouds” exist.

5. Electron Configurations Example: Silicon

6. Si

7. Electron Configurations Start from Hydrogen and work towards Silicon, filling in all of the orbitals as you progress…

8. Si 1s 2 2s 2 2p 6 3s 2 3p 2

9. Electron Configurations For larger atoms change the energy level for the d-block and f-block. For the d you subtract 1. For the f you subtract 2.

11. Electron Configurations Example: Mercury (Hg) 80e - Starting from Hydrogen:

12. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 Hg 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10

13. Noble Gas Configuration For elements with long electron configurations, this can shorten your answer. Noble Gases are located in the final column on the periodic table.

14. Noble Gas Configuration Example: W, atomic number 74

15. Noble Gas Configuration Work backwards from your element to find the noble gas that comes before it. For W, the noble gas before it is Xe.

16. Noble Gas Configuration To start writing the configuration:

17. Noble Gas Configuration Then, continue writing the configuration like before, starting from Xe. 6s 2 4f 14 5d 4