Question

which electron configuration represents a violation of hunds rule for an atom in its ground state?

Explanation:

Hund's rule states that electrons in degenerate orbitals (same - energy orbitals like the three 2p orbitals) first fill each orbital singly with parallel spins before pairing up. In the fourth option, in the 2p sub - shell, electrons are paired in one orbital before all the 2p orbitals have one electron each, which violates Hund's rule.

Answer:

The electron configuration with 1s $\uparrow\downarrow$, 2s $\uparrow\downarrow$, 2p $\uparrow\downarrow$ $\square$ $\square$ represents a violation of Hund's rule.