Quantum Chemistry

1. Quantum Chemistry • Describes the placement of the electrons in an atom by using the four Quantum Numbers: • norEnergy Level: as the atom becomes larger, the energy level increases (1, 2, 3, …)

2. Quantum Chemistry • lorOrbital: the electrons exist around the nucleus in discreet areas called orbitals (s, p, d, f)

3. Quantum Chemistry • m ormagnetic: the orbital can be detected magnetically to be divided into sub-orbitals • s = 1; p = 3; d = 5; f = 7 • s or spin: each electron in the sub orbital spins in the opposite direction ( )

4. Quantum Chemistry • Pauli Exclusion Principle: No two electrons in the same atom can have the same Quantum Number

5. Quantum Chemistry • The shape of the s, p, d and f orbitals allow for each sub orbital to contain 2 electrons of opposite spin.

6. Shape of S-Orbital 1 S Sub-Orbital

7. y y z z x x Shape of P-Orbitals y z x Px Sub-Orbital Py Sub-Orbital Pz Sub-Orbital 3 P Sub-Orbitals

8. y y y y y z z z z z x x x x x dx2-y2 dyz dz2 dxz dxy Shape of d-Orbitals 5 d Sub-Orbitals

9. y y z z x x P Orbital S Orbital Electron Orbitals

10. Quantum Chemistry • The energies of atomic orbitals increase as the principal quantum number n increases. • As the quantum number l increases, the energies between the orbitals also increases.

11. Quantum Chemistry • Each electron added to a sub-orbital is represented as an arrow pointed “up” then “down”

12. y z x Energy Energy Electron Orbital Energies py pz px s

13. y z x Energy Energy Electron Orbital Energies An Electron Energy Diagram can be drawn representing each electron which has been placed in a sub-orbital • all sub orbitals at a • given Energy must • have an arrow • pointing “up” before • placing one “down”. Py Pz Px S

14. Note that the energy level for the 4s orbital is lower than that of the 3d orbital, so the electrons will fill the 4s orbital first. Energy 4px 3px 2px 4py 3py 2py 3pz 2pz 4pz Electron Orbital Energies(Energy Diagram) 5s 3dx 3dy 3dx 3dy 3dz 4s 3s 2s 1s

15. 5s 3dx 3dy 3dx 3dy 3dz 4s 3s Energy 3Px 4Px 2Px 3Py 4Py 2Py 3Pz 2Pz 4Pz 2s 1s The Energy Diagram of Boron, with 5 Electrons would be:

16. 5s 3dx 3dy 3dx 3dy 3dz 4s 3s Energy 2Px 4Px 3Px 4Py 2Py 3Py 4Pz 3Pz 2Pz 2s 1s The Energy diagram of Chlorine with 17 electrons would be:

17. 5s 3dx 3dy 3dx 3dy 3dz 4s 3s Energy 2Px 4Px 3Px 4Py 2Py 3Py 4Pz 3Pz 2Pz 2s 1s What is the Energy Diagram for Manganese?