Electron spin and the Pauli exclusion principle

Electron spin and the Pauli exclusion principle - • The...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Electron spin and the Pauli exclusion principle What determines the orbitals in which the electrons reside? How do the electrons populate the available orbitals? Line spectra revisited. .. Lines which were thought to be single lines actually were composed of two very closely spaced lines Thus, there were twice as many energy levels as there were "supposed" to be It was proposed (Uhlenbeck and Goudsmit, 1925) that electrons have yet another quantum property called electron spin: A new quantum number for the electron called the electron spin quantum number , or m s m s has a value of +1/2 or -1/2 The electron spin quantum number characterized the "direction of spin" of the electron o A spinning charge produces a magnetic field o The opposite spins produce opposite magnetic fields which results in the splitting of the line spectrum into two closely spaced lines Electron spin is crucial for understanding the electron structures of atoms:
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: • The Pauli exclusion principle (Wolfgang Pauli, 1925) states that no two electrons in an atom can have the same set of four quantum numbers ( n, l, m l and m s ) • For a given orbital (e.g. 2 p z ) the values of n , l and m l are fixed . Thus, if we want to put more than one electron into an orbital we must assign unique values to the magnetic spin ( m s quantum number) • the m s quantum number can only have two values (+1/2, and -1/2) therefore, only two electrons at most can occupy the same orbital, and they have opposite values for magnetic spin What are the consequences of magnetic spin quantum number and the Pauli exclusion principle? • If we know the number of electrons in an atom we can assign probable quantum numbers and know something about their orbital shapes • Provides an understanding for the periodic nature of the elements...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online