1. Quantum Mechanics

2. Quantum Mechanical Model of the Atom This is the current model of the atom (…ish) Also includes an electron cloud – an area of probability of finding an electron calculated mathematically –Electrons are moving in waves- not in orderly, straight orbitals. These waves connect to our ideas about the electromagnetic spectrum.

3. Electron movement In orbitals NOT ORBITS Basketball court model –In a given region around the nucleus based on energy level

4. Structure of Energy Levels Most broad: electrons exist in atoms Within atoms: electrons are Quantum Levels (n) Within quantum levels: there are sublevels –s: 2 electrons in 1 orbital –p: 6 electrons in 3 orbitals –d: 10 electrons in 5 orbitals –f: 14 electrons in 7 orbitals Where are they on the periodic table?

5. Number of sublevels in each quantum level Follow the periodic table!! n = level 1 has only s orbital shapes n = level 2 has s and p orbital shapes The quantum levels do not always match up with the rows of the periodic table… n = 3 has s,p, and d orbitals n = 4 has s,p,d, and f orbitals

6. Notation Electron configurations! Break the configurations up by: –n (Quantum Level) –Sublevel (s, p, d, f) –Number of electrons within that sublevel (written as a superscript)

7. Electron configuration The distribution of electrons among the sublevels of an atom. ALWAYS letters and numbers Fill out total number of electrons for each element shown on your notes page (H through B and Mn)

8. Orbital Diagrams Orbital diagrams will always use boxes- these boxes show the orbitals in an atom. Follow the sublevels, arrows for each electron Try these: –Oxygen –Chlorine

9. Rules Aufbau Principle (snake diagram) –You must fill a sublevel before moving on to the next one. The periodic order must be obeyed! Pauli Exclusion Principle –A maximum of two electrons can share an orbital. If two electrons share the same orbital, they will have opposite spin. Hund’s Rule (Roommate rule) –You must put one electron into each orbital before pairing them up.