Atomic Structure Flashcards
Pauli principle
Max of 2 electrons with opposite spins can occupy the same orbital
Aufbau principle
Lowest energy atomic orbitals are filled first
Why are lowest energy AO filled first
Better penetration and less shielding are more exposed to positive nucleus so have a lower energy
Hunds first rule
Ground state electronic configuration has max number of unpaired electrons with spins parallel
Spin-spin interaction
Paired electrons overlap and interact so have high energy but parallel electrons avoid one another and dont interact so lower energy
Orbital interaction
Electron-electron electrostatic repulsion depends on orbital occupancy
Spin-orbit interaction
Each electron has intrinsic magnetic moment identified with its spin, when orbitals move electrons circulate and different magnetic moments of each electrons will interact with repulsion if the poles point in the same direction
Degeneracy of total spin angular momentum
2S + 1
Degeneracy of total orbital angular momentum
2L + 1
Value of l for s, p, d, f AO
0, 1, 2, 3
Value of L and S for filled AO
L = 0 and S = 0
Miicrostates
Unique arrangements of electrons within AO that obey Pauli principle
What micro state is lowest in energy
Greatest multiplicity (spin) lies lowest, for given multiplicity highest L lies lowest, for < half filled shells lowest J lies lowest and for > half filled shells highest J lies lowest
Spin selection rule
ΔS = 0
Orbital selection rule
ΔL = 0 or ΔL = +-1
