1. Expanding the Theory of the Atom
Chapter 7

2. Energy levels and Sublevels
We already know that electrons occupy energy levels-regions in space around the nucleus
There are also sublevels – divisions within an energy level – identified as s, p, d, or f

4. Energy Levels and Sublevels (con’d)
The order of sublevels from lowest to highest energy is s, p, d, f
1st energy level has 1 sublevel -1s
2nd has 2 sublevels – 2s, 2p
3rd has 3 – 3s, 3p, 3d
4th has s, 4p, 4d, 4f
So within the 4th energy level the 4s is the lowest energy, and the 4 f is the highest

5. Sublevels
Just as energy levels have a maximum number of electrons they can hold, so do sublevels
An s sublevel can hold 2 e-
P can hold 6
D can hold 10
F can hold 14

6. Heisenberg
A scientist named Werner Heisenberg concluded it is impossible to accurately measure both the location and energy of an electron at the same time – the Heisenberg uncertainty principle.
Relates to the electron cloud model (p. 239)

7. Orbitals Sublevels are further divided into orbitals.
An orbital can hold a maximum of 2 e-
The s sublevel has 1 orbital (2 e- max)
P has 3 orbitals (6 e- max)
D has 5 orbitals (10 max)
F has 7 orbitals ( 14 max)
Diagrams p. 239

8. Electron Configuration
In an atom electrons are distributed among the energy levels, sublevels, and orbitals in the way that creates the most stable arrangement – the lowest energy
This most stable arrangement of electrons in sublevels and orbitals is called electron configuration.

9. Electron configuration (con’d)
Electrons fill orbitals and sublevels from the innermost (closest to the nucleus) to the outermost (furthest from the nucleus)

10. Helpful diagram for Electron Configuration (Con’d)

11. Helpful diagram for Electron Configuration (Con’d)

12. When Doing an Electron Configuration
Figure out how many electrons are in the atom you are trying to figure out
Fill electron into lower energy levels first
Follow order of filling
Remember how many electrons each level can hold: s holds 2, p holds 6, d 10, f 14

13. When Doing an Electron Configuration (Con’d)
Write the configuration in this format
Energy Level (number), sublevel(letter), Number of electrons in that sublevel (superscript)
Ex: 1s2 2s2 2p1

14. Shorthand (noble gas) notation
Shows the electron filling starting from the previous noble gas.
Ex: P: [Ne] 3s2 3p3

15. Lets Try Some