Question

which 2p subshell has the electrons properly placed?
2p ↑↑ ↑↑ ↑
2p ↑↓ ↑ ↓
2p ↑↑ ↑↑ _
2p ↑↓ ↑↓ ↑
2p ↑↑ ↑ ↑

Explanation:

According to Hund's rule, electrons in degenerate orbitals (orbitals of the same energy in a sub - shell like the three 2p orbitals) first fill each orbital singly with parallel spins before pairing up. In a 2p sub - shell with 3 orbitals, the proper electron placement follows this rule.

Answer:

The option with electrons filling each of the three 2p orbitals singly with parallel spins (e.g., arrows all pointing up) before any pairing is the correct one. Among the given options, the one that follows Hund's rule is the correct answer. Without specific labels for the options, it's not possible to give an option identifier, but the correct configuration has electrons filling the three 2p orbitals singly first with parallel spins.