The statement that "the lowest energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the pauli principle in a particular set of degenerate orbitals" is known as: a. the quantum model b. hund's rule c. the aufbau principle d. heisenberg uncertainty principle e. the pauli exclusion principle

B. Hund's rule

Explanation:

Hund's rule -

According to Hund's rule ,

As, the electrons are negatively charged and hence , like poles repel , so they repel each other in order to stabilizes themselves and hence ,  the electron firstly occupies a vacant orbital , before actually pairing up , so as to reduce repulsion .

The rule of maximum multiplicity states that ,

The term with the lowest energy is the one with the highest value of the spin multiplicity .

hence , the statement given in the question is about Hund's rule .

2b2t

explanation:

2b2t

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.