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

Quantum Chemistry l or Orbital: the electrons exist around the nucleus in discreet areas called orbitals (s, p, d, f)

Quantum Chemistry m or magnetic: 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 ( )

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

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

Shape of S-Orbital 1 S Sub-Orbital

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

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

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

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.

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

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

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

Electron Orbital Energies (Energy Diagram) 4px 4py 4pz Energy 3dx 3dy 3dx 3dy 3dz 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. 4s 3px 3py 3pz 3s 2px 2py 2pz 2s 1s

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

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

What is the Energy Diagram for Manganese? 2Px 2Py 2Pz 4Px 4Py 4Pz 3Px 3Py 3Pz 3dx 3dy 3dz