18. The Pauli exclusion principle - application to fermions (definition), the explanation of elements properties in the periodic table. (4p.)

Question 1

The Pauli exclusion principle

Answer 1

The Pauli exclusion principle states No two electrons in an atom can have the same four quantum numbers: n, l, ml, ms

Electrons on one orbital must have oposite spins.

There can be maximally 2 electrons on one orbital.

Question 2

The Pauli exclusion principle - application to fermions (definition)

Answer 2

fermions are particles which obey Fermi-Dirac statistrics.
2 fermions can simultaneously occupy the same quantum state.

Question 3

The Pauli exclusion principle - the explanation of elements properties of lanthanides and actinides in the periodic table.

Answer 3

lanthanides and actinides are f block elements.
f block elements have high melting points and f block elements have variable oxidation states
f block have their valance electrons on the f orbital.