Unformatted text preview: umber, Z
2. Electrons fill orbitals starting with the lowest n and moving
upwards, with no more than two electrons per orbital (Aufbau
principle) Aufbau means to build up in German. 3. No two electrons can fill one orbital with the same spin (Pauli’s
exclusion principle). if they have the same spin. 4. degenerate
Hund’s Rule: for ___________ orbitals, e- fill each orbital
singly before any orbital gets a 2nd e-, i.e., e- are distributed in
amongst the orbitals of a subshell in such a way as to yield
the maximum number of unpaired e-. if u have 3 orbitals and 3 electrons--> each orbital will get one electron. prior to
adding a second electron, u have to make sure that all orbitals have atleast one
electron. Electron spin and the Pauli Exclusion Principle
So far we have encountered three quantum numbers: n, l, and ml.
However, as scientists applied the quantum-mechanic model to
experimental data they discovered it was not quite right. There
was something missing.
Consider the Stern-Gerlach experiment: they found that electrons...
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