Question

multiple choice question
according to ____, a maximum of two electrons can occupy a single atomic orbital, but only if the electrons have opposite spins.
the aufbau principle
the pauli exclusion principle
the heisenberg uncertainty principle
hunds rule

Explanation:

The Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers. In a single atomic orbital, which is defined by a set of quantum numbers, only two electrons can be present. These two electrons must have opposite spins (one with spin +1/2 and the other with spin -1/2) to satisfy the principle.

• The aufbau principle is about the filling of orbitals in order of increasing energy.
• The Heisenberg uncertainty principle is about the inability to simultaneously know the exact position and momentum of a particle.
• Hund's rule is about electrons filling degenerate orbitals singly first before pairing up.

So, the principle that matches the description in the question is the Pauli exclusion principle.

Answer:

the Pauli exclusion principle